Field assemblies and methods of making same

• US 20050057113A1
• Filed: 09/03/2004
• Published: 03/17/2005
• Est. Priority Date: 09/05/2003
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Kusmierski, Robert G., Du, Hung T., Verbrugge, Brandon L., Smith, David J., Zemlok, Michael A., Ortt, Earl M., Stone, John C., Agnes, Michael J.
• Granted Patent: US 7,078,843 B2
• Time in Patent Office: Days
• US Class Current: 310/216.91
• CPC Class Codes: H02K 1/148 Sectional cores H02K1/141 takes precedence
• CPC Class Codes: H02K 1/18 Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures
• CPC Class Codes: H02K 15/0435 Wound windings
• CPC Class Codes: H02K 15/10 Applying solid insulation to windings, stators or rotors
• CPC Class Codes: H02K 15/12 Impregnating, heating or drying of windings, stators, rotors or machines
• CPC Class Codes: H02K 3/325 for windings on salient poles, such as claw-shaped poles
• CPC Class Codes: H02K 3/522 for generally annular cores with salient poles
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine

Abstract

An electric motor, power tool using the electric motor, and method of making the electric motor includes making a stator by separately forming pole pieces, return path pieces and field coils. The field coils are placed over necks of the pole path pieces and the return path pieces are affixed to the pole pieces. An armature having an outside diameter of at least 0.625 the outside diameter of the stator is placed in the stator. In an aspect, the field coils are formed so that they extend beyond pole tips of the pole pieces.

Claims

1. A method of making an electric motor, comprising:

a. forming field coils to a predetermined shape;

b. forming pole pieces and return path pieces;

c. placing the field coils on the pole pieces after forming them to the predetermined shape;

d. mating the pole pieces and return path pieces after placing the field coils on the pole pieces to form a stator having an outside diameter; and

e. placing an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator in the stator.

2. The method of claim 1 including forming the field coils so that they extend beyond pole tips of the pole pieces when they are placed on the pole pieces.

3. The method of claim 1 including forming the field coils to a net shape.

4. The method of claim 1 including bonding wires of each field coil together prior to placing the field coils on the pole pieces.

5. The method of claim 1 including bonding wires of each field coil together when forming the field coils.

6. The method of claim 1 including encapsulating the field coils in plastic prior to placing the field coils on the pole pieces.

7. The method of claim 6 including encapsulating the field coils in a thermoset plastic.

8. The method of claim 6 including encapsulating the field coils in a thermoplastic.

9. The method of claim 6 including encapsulating the field coils in liquid silicon rubber.

10. The method of claim 1 including wrapping each portion of each field coil that will be disposed between one of the pole pieces and one of the return path pieces mated to that pole piece with an insulating slot liner made of a layer of insulation material having at least one of a B-stage thermosetting adhesive and a thermoplastic adhesive on at least one side prior to placing the field coil on that pole piece and after forming the field coil to the predetermined shape and after the return path pieces have been mated to the pole pieces, heating the stator to activate the adhesive to bond the insulating slot liners to the respective field coils and to the respective return path pieces and pole pieces abutting the field coils to secure them together.

11. The method of claim 1 including placing an insulating sleeve over each portion of each field coil that will be disposed between a surface of a pole piece and a surface of a return path piece when the return path pieces have been mated to the pole pieces.

12. The method of claim 1 including placing an insulating sleeve having compliant material on at least one of its surfaces over each portion of each field coil that will be disposed between a surface of a pole piece and a surface of a return path piece when the return path pieces have been mated to the pole pieces.

13. The method of claim 1 including placing an insulating sleeve made of at least one of liquid silicon rubber, insulating paper and insulating plastic film over each portion of each field coil that will be disposed between a surface of a pole piece and a surface of a return path piece when the return path pieces have been mated to the pole pieces.

14. The method of claim 13 including providing an interference fit between each portion of the field coil over which one of the insulating sleeves is placed and at least one of the pole pieces and return path piece between which that portion of that field coil is disposed by providing at least one compression rib on a surface of the insulating sleeve that abuts one of the pole piece and return path piece between which that portion of the field coil is disposed.

15. The method of claim 1 including securing each pole piece to the return path pieces that are mated to it by providing mating features in that pole piece and those return path pieces and deforming the mating features together to secure that pole piece to those return path pieces.

16. The method of claim 1 including securing each pole piece to the return path pieces that are mated to it by providing receiving pockets in portions of the neck of the pole piece and fingers on ends of those return path pieces, inserting the fingers into the recesses and deforming the portions of the neck of the pole piece having the recesses and the fingers of the return path pieces together.

17. The method of claim 16 including forming the field coils to a net shape and so that they extend beyond tips of the pole pieces when they are placed on the pole pieces.

122. The method of claim 1 including providing lead wires for the field coils by insulating lengths of coil ends of the field coils with one of TFE and PTFE tubing.

160. The method of claim 1 wherein the motor is thermally balanced.

166. The method of claim 1 including forming the field coils by winding them with at least two different sizes of wire.

18. A method of making an electric motor, comprising:

a. forming field coils so that they extend beyond pole tips of pole pieces when they are placed on the pole pieces;

b. forming return path pieces and the pole pieces;

c. placing the field coils on the pole pieces;

d. mating the pole pieces and return path pieces to form a stator having an outside diameter; and

e. placing an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator in the stator.

19. The method of claim 18 including forming the field coils to have an included angle of at least 110% of an included angle of the pole tips.

20. The method of claim 18 including forming the field coils to have an included angle of at least 125% of an included angle of the pole tips.

21. The method of claim 18 including forming the field coils to have an included angle of at least 140% of an included angle of the pole tips.

22. The method of claim 18 including forming the field coils to have an included angle of at least 155% of an included angle of the pole tips.

23. The method of claim 18 including forming the field coils to have a packing factor of at least 60%.

24. The method of claim 18 including forming the field coils to have a packing factor of at least 70%.

25. The method of claim 18 including forming the field coils to have a packing factor of at least 80%.

26. The method of claim 18 including forming the field coils to have a packing factor of at least 85%.

27. The method of claim 18 including forming the field coils to have a packing factor of at least 60% and an included angle of at least 110% of an included angle of the pole tips.

28. The method of claim 18 including forming the field coils to have a packing factor of at least 70% and an included angle of at least 110% of an included angle of the pole tips.

29. The method of claim 18 including forming the field coils to have a packing factor of at least 80% and an included angle of at least 110% of an included angle of the pole tips.

30. The method of claim 18 including forming the field coils to have a packing factor of at least 85% and an included angle of at least 110% of an included angle of the pole tips.

31. The method of claim 18 including forming the field coils to have a packing factor of at least 60% and an included angle of at least 125% of an included angle of the pole tips.

32. The method of claim 18 including forming the field coils to have a packing factor of at least 70% and an included angle of at least 125% of an included angle of the pole tips.

33. The method of claim 18 including forming the field coils to have a packing factor of at least 80% and an included angle of at least 125% of an included angle of the pole tips.

34. The method of claim 18 including forming the field coils to have a packing factor of at least 85% and an included angle of at least 125% of an included angle of the pole tips.

35. The method of claim 18 including forming the field coils to have a packing factor of at least 60% and an included angle of at least 140% of an included angle of the pole tips.

36. The method of claim 18 including forming the field coils to have a packing factor of at least 70% and an included angle of at least 140% of an included angle of the pole tips.

37. The method of claim 18 including forming the field coils to have a packing factor of at least 80% and an included angle of at least 140% of an included angle of the pole tips.

38. The method of claim 18 including forming the field coils to have a packing factor of at least 85% and an included angle of at least 140% of an included angle of the pole tips.

39. The method of claim 18 including forming the field coils to have a packing factor of at least 60% and an included angle of at least 155% of an included angle of the pole tips.

40. The method of claim 18 including forming the field coils to have a packing factor of at least 70% and an included angle of at least 155% of an included angle of the pole tips.

41. The method of claim 18 including forming the field coils to have a packing factor of at least 80% and an included angle of at least 155% of an included angle of the pole tips.

42. The method of claim 18 including forming the field coils to have a packing factor of at least 85% and an included angle of at least 155% of an included angle of the pole tips.

43. The method of claim 18 including forming the field coils to a net shape and bonding wires of each field coil together prior to placing the field coils on the pole pieces.

44. The method of claim 43 including placing an insulating sleeve over each portion of each field coil that is disposed between one of the pole pieces and one of the return path pieces.

45. The method of claim 44 including providing compliant material on at least one surface of each insulating sleeve that abuts one of the pole pieces and return path pieces.

46. The method of claim 44 including providing an interference fit between each portion of the field coil over which one of the insulating sleeves is placed and at least one of the pole piece and return path piece between which that portion of that field coil is disposed by providing at least one compression rib on a surface of the insulating sleeve that abuts one of the pole piece and return path piece between which that portion of the field coil is disposed.

47. The method of claim 44 wherein placing an insulating sleeve over each portion of each field coil includes doing so with an insulating sleeve made of at least one of liquid silicon rubber, insulating paper and insulating plastic film.

48. The method of claim 43 including encapsulating each field coil in plastic prior to placing the field coil on one of the pole pieces.

49. The method of claim 18 including securing each pole piece to the return path pieces that are mated to it by providing mating features in that pole piece and those return path pieces and deforming the mating features together to secure that pole piece to those return path pieces.

50. The method of claim 18 including securing each pole piece to the return path pieces that are mated to it by providing receiving pockets in portions of the neck of the pole piece and fingers on ends of those return path pieces, inserting the fingers into the recesses and deforming the portions of the neck of the pole piece having the recesses and the fingers of the return path pieces together.

117. The method of claim 18 including wrapping each portion of each field coil that will be disposed between one of the pole pieces and one of the return path pieces mated to that pole piece with an insulating slot liner made of a layer of insulation material having at least one of a B-stage thermosetting adhesive and a thermoplastic adhesive on at least one side prior to placing the field coil on that pole piece and after forming the field coil to the predetermined shape and after the return path pieces have been mated to the, pole pieces, heating the field coils to activate the adhesive to bond the insulating slot liners to the respective field coils and to the respective return path pieces and pole pieces abutting the field coils to secure them together.

123. The method of claim 18 including providing lead wires for the field coils by insulating lengths of coil ends of the field coils with one of TFE and PTFE tubing.

161. The method of claim 18 wherein the motor is thermally balanced.

167. The method of claim 18 including forming the field coils by winding them with at least two different sizes of wire.

51. An electric motor, comprising:

a. a stator having pole pieces on which field coils are disposed and return path pieces mated to the pole pieces;

the stator having an outside diameter; and

b. an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator.

52. The motor of claim 51 wherein the field coils extend beyond pole tips of the pole pieces on which they are disposed.

53. The motor of claim 51 including insulating sleeves in which the field coils are received, the insulating sleeves disposed between the field coils and surfaces of the pole pieces and return path pieces that are adjacent the field coils.

54. The motor of claim 51 wherein the pole pieces and return path pieces have mating features that are deformed together to secure the return path pieces to the pole pieces.

55. The motor of claim 51 wherein each pole piece has a neck with opposed receiving pockets therein, each return path piece having a finger at each end which is received in a respective pocket of a pole piece and portions of the necks of the pole pieces having the receiving pockets and the fingers deformed together to secure the pole pieces to the return path pieces.

118. The motor of claim 51 including an insulating slot liner made of a layer of insulation material with at least one of a B-stage thermosetting adhesive and a thermoplastic adhesive on at least one side wrapped around each portion of each field coil disposed between one of the pole pieces and one of the return path pieces mated to that pole piece, the adhesive activated during assembly of the stator and bonding the layer of insulation material to that field coil and those pole and return path pieces to secure them together.

124. The motor of claim 51 wherein lengths of coil ends of each field coil are insulated with one of TFE and PTFE tubing to provide lead wires for each field coil.

162. The motor of claim 51 wherein the motor is thermally balanced.

168. The motor of claim 51 wherein the field coils include windings of at least two different sizes of wires.

56. An electric motor, comprising:

a. a stator having pole pieces on which field coils are disposed and return path pieces mated to the pole pieces, the field coils extending beyond pole tips of the pole pieces on which they are disposed, the stator having an outside diameter; and

b. an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator.

57. The motor of claim 56 wherein the field coils have an included angle of at least 110% of an included angle of the pole tips.

58. The motor of claim 56 wherein the field coils have an included angle of at least 125% of an included angle of the pole tips.

59. The motor of claim 56 wherein the field coils have an included angle of at least 140% of an included angle of the pole tips.

60. The motor of claim 56 wherein the field coils have an included angle of at least 155% of an included angle of the pole tips.

61. The motor of claim 56 wherein the field coils have a packing factor of at least 60%.

62. The motor of claim 56 wherein the field coils have a packing factor of at least 70%.

63. The motor of claim 56 wherein the field coils have a packing factor of at least 80%.

64. The motor of claim 56 wherein the field coils have a packing factor of at least 85%.

65. The motor of claim 56 wherein the field coils have a packing factor of at least 60% and an included angle of at least 110% of an included angle of the pole tips.

66. The motor of claim 56 wherein the field coils have a packing factor of at least 70% and an included angle of at least 110% of an included angle of the pole tips.

67. The motor of claim 56 wherein the field coils have a packing factor of at least 80% and an included angle of at least 110% of an included angle of the pole tips.

68. The motor of claim 56 wherein the field coils have a packing factor of at least 85% and an included angle of at least 110% of an included angle of the pole tips.

69. The motor of claim 56 wherein the field coils have a packing factor of at least 60% and an included angle of at least 125% of an included angle of the pole tips.

70. The motor of claim 56 wherein the field coils have a packing factor of at least 70% and an included angle of at least 125% of an included angle of the pole tips.

71. The motor of claim 56 wherein the field coils have a packing factor of at least 80% and an included angle of at least 125% of an included angle of the pole tips.

72. The motor of claim 56 wherein the field coils have a packing factor of at least 85% and an included angle of at least 125% of an included angle of the pole tips.

73. The motor of claim 56 wherein the field coils have a packing factor of at least 60% and an included angle of at least 140% of an included angle of the pole tips.

74. The motor of claim 56 wherein the field coils have a packing factor of at least 70% and an included angle of at least 140% of an included angle of the pole tips.

75. The motor of claim 56 wherein the field coils have a packing factor of at least 80% and an included angle of at least 140% of an included angle of the pole tips.

76. The motor of claim 56 wherein the field coils have a packing factor of at least 85% and an included angle of at least 140% of an included angle of the pole tips.

77. The motor of claim 56 wherein the field coils have a packing factor of at least 60% and an included angle of at least 155% of an included angle of the pole tips.

78. The motor of claim 56 wherein the field coils have a packing factor of at least 70% and an included angle of at least 155% of an included angle of the pole tips.

79. The motor of claim 56 wherein the field coils have a packing factor of at least 80% and an included angle of at least 155% of an included angle of the pole tips.

80. The motor of claim 56 wherein the field coils have a packing factor of at least 85% and an included angle of at least 155% of an included angle of the pole tips.

81. The motor of claim 56 including insulating sleeves in which the field coils are received, the insulating sleeves disposed between the field coils and surfaces of the pole pieces and return path pieces that are adjacent the field coils.

82. The motor of claim 56 wherein the pole pieces and return path pieces have mating features that are deformed together to secure the return path pieces to the pole pieces.

83. The motor of claim 56 wherein each pole piece has a neck with opposed receiving pockets therein, each return path piece having a finger at each end which is received in a respective pocket of a pole piece and portions of the necks of the pole pieces having the receiving pockets and the fingers deformed together to secure the pole pieces to the return path pieces.

119. The motor of claim 56 including an insulating slot liner made of a layer of insulation material with at least one of a B-stage thermosetting adhesive and a thermoplastic adhesive on at least one side wrapped around each portion of each field coil disposed between one of the pole pieces and one of the return path pieces mated to that pole piece, the adhesive activated during assembly of the stator and bonding the layer of insulation material to that field coil and those pole and return path pieces to secure them together.

125. The motor of claim 56 wherein lengths of coil ends of each field coil are insulated with one of TFE and PTFE tubing to provide lead wires for each field coil.

128. The motor of claim 56 wherein at least one of the pole pieces and return path pieces are made of insulated iron powder.

163. The motor of claim 56 wherein the motor is thermally balanced.

169. The motor of claim 56 wherein the field coils include windings of at least two different sizes of wires.

84. A hand-held power tool, comprising:

a. a housing; and

b. a motor disposed in the housing, the motor including;

i. a stator having pole pieces on which field coils are disposed and return path pieces mated to the pole pieces, the stator having an outside diameter; and

ii. an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator.

85. The power tool of claim 84 wherein the field coils extend beyond tips of the pole pieces on which they are disposed.

86. The power tool of claim 84 including insulating sleeves in which the field coils are received, the insulating sleeves disposed between the field coils and surfaces of the pole pieces and return path pieces that are adjacent the field coils.

87. The power tool of claim 84 wherein the pole pieces and return path pieces have mating features that are deformed together to secure the return path pieces to the pole pieces.

88. The power tool of claim 84 wherein each pole piece has a neck with opposed receiving pockets therein, each return path piece having a finger at each end which is received in a respective pocket of a pole piece and portions of the necks of the pole pieces having the receiving pockets and the fingers deformed together to secure the pole pieces to the return path pieces.

120. The power tool of claim 84 including an insulating slot liner made of a layer of insulation material with at least one of a B-stage thermosetting adhesive and a thermoplastic adhesive on at least one side wrapped around each portion of each field coil disposed between one of the pole pieces and one of the return path pieces mated to that pole piece, the adhesive activated during assembly of the stator and bonding the layer of insulation material to that field coil and those pole and return path pieces to secure them together.

126. The power tool of claim 84 wherein lengths of coil ends of each field coil are insulated with one of TFE and PTFE tubing to provide lead wires for each field coil.

164. The power tool of claim 84 wherein the motor is thermally balanced.

170. The power tool of claim 84 wherein the field coils include windings of at least two different sizes of wires.

89. A hand-held power tool, comprising:

a. a housing;

b. a motor disposed in the housing;

c. the motor including;

i. a stator having pole pieces on which field coils are disposed and return path pieces mated to the pole pieces, the field coils extending beyond pole tips of the pole pieces on which they are disposed, the stator having an outside diameter; and

ii. an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator.

90. The power tool of claim 89 wherein the field coils have an included angle of at least 110% of an included angle of the pole tips.

91. The power tool of claim 89 wherein the field coils have an included angle of at least 125% of an included angle of the pole tips.

92. The power tool of claim 89 wherein the field coils have an included angle of at least 140% of an included angle of the pole tips.

93. The power tool of claim 89 wherein the field coils have an included angle of at least 155% of an included angle of the pole tips.

94. The power tool of claim 89 wherein the field coils have a packing factor of at least 60%.

95. The power tool of claim 89 wherein the field coils have a packing factor of at least 70%.

96. The power tool of claim 89 wherein the field coils have a packing factor of at least 80%.

97. The power tool of claim 89 wherein the field coils have a packing factor of at least 85%.

98. The power tool of claim 89 wherein the field coils have a packing factor of at least 60% and an included angle of at least 110% of an included angle of the pole tips.

99. The power tool of claim 89 wherein the field coils have a packing factor of at least 70% and an included angle of at least 110% of an included angle of the pole tips.

100. The power tool of claim 89 wherein the field coils have a packing factor of at least 80% and an included angle of at least 110% of an included angle of the pole tips.

101. The power tool of claim 89 wherein the field coils have a packing factor of at least 85% and an included angle of at least 110% of an included angle of the pole tips.

102. The power tool of claim 89 wherein the field coils have a packing factor of at least 60% and an included angle of at least 125% of an included angle of the pole tips.

103. The power tool of claim 89 wherein the field coils have a packing factor of at least 70% and an included angle of at least 125% of an included angle of the pole tips.

104. The power tool of claim 89 wherein the field coils have a packing factor of at least 80% and an included angle of at least 125% of an included angle of the pole tips.

105. The power tool of claim 89 wherein the field coils have a packing factor of at least 85% and an included angle of at least 125% of an included angle of the pole tips.

106. The power tool of claim 89 wherein the field coils have a packing factor of at least 60% and an included angle of at least 140% of an included angle of the pole tips.

107. The power tool of claim 89 wherein the field coils have a packing factor of at least 70% and an included angle of at least 140% of an included angle of the pole tips.

108. The power tool of claim 89 wherein the field coils have a packing factor of at least 80% and an included angle of at least 140% of an included angle of the pole tips.

109. The power tool of claim 89 wherein the field coils have a packing factor of at least 85% and an included angle of at least 140% of an included angle of the pole tips.

110. The power tool of claim 89 wherein the field coils have a packing factor of at least 60% and an included angle of at least 155% of an included angle of the pole tips.

111. The power tool of claim 89 wherein the field coils have a packing factor of at least 70% and an included angle of at least 155% of an included angle of the pole tips.

112. The power tool of claim 89 wherein the field coils have a packing factor of at least 80% and an included angle of at least 155% of an included angle of the pole tips.

113. The power tool of claim 89 wherein the field coils have a packing factor of at least 85% and an included angle of at least 155% of an included angle of the pole tips.

114. The power tool of claim 89 including insulating sleeves in which the field coils are received, the insulating sleeves disposed between the field coils and surfaces of the pole pieces and return path pieces that are adjacent the field coils.

115. The power tool of claim 89 wherein the pole pieces and return path pieces have mating features that are deformed together to secure the return path pieces to the pole pieces.

116. The power tool of claim 89 wherein each pole piece has a neck with opposed receiving pockets therein, each return path piece having a finger at each end which is received in a respective pocket of a pole piece and portions of the necks of the pole pieces having the receiving pockets and the fingers deformed together to secure the pole pieces to the return path pieces.

121. The power tool of claim 89 including an insulating slot liner made of a layer of insulation material with at least one of a B-stage thermosetting adhesive and a thermoplastic adhesive on at least one side wrapped around each portion of each field coil disposed between one of the pole pieces and one of the return path pieces mated to that pole piece, the adhesive activated during assembly of the stator and bonding the layer of insulation material to that field coil and those pole and return path pieces to secure the together.

127. The power tool of claim 89 wherein lengths of coil ends of each field coil are insulated with one of TFE and PTFE tubing to provide lead wires for each field coil.

129. The power tool of claim 89 wherein at least one of the pole pieces and return path pieces are made of insulated iron powder.

165. The power tool of claim 89 wherein the motor is thermally balanced.

171. The power tool of claim 89 wherein the field coils include windings of at least two different sizes of wires.

130. A method of making an electric motor of a given frame size with increased power compared to a conventional needle wound motor of the same frame size, comprising:

a. forming field coils so that they extend beyond pole tips of pole pieces when they are placed on the pole pieces;

b. forming return path pieces and the pole pieces;

c. placing the field coils on the pole pieces;

d. mating the pole pieces and return path pieces to form a stator having an outside diameter;

e. winding an armature that has an outside diameter that is at least 0.625 of the outside diameter of the stator and placing it in the stator;

f. wherein forming the field coils includes doing so to provide the motor with a maximum power output at a desired speed that is at least thirty percent greater than a maximum power output at the desired speed of the conventional needle wound motor of the same frame size.

131. The method of claim 130 wherein the electric motor has a 55 mm frame size and a maximum power output at 38,000 rpm of at least 1050 watts.

132. The method of claim 130 wherein the electric motor has a 59 mm frame size and a maximum power output at 38,000 rpm of at least 1300 watts.

133. The method of claim 130 wherein the electric motor has a 59 mm frame size and a maximum power output at 38,000 rpm of at least 1600 watts.

134. The method of claim 130 including forming the field coils to have an included angle of at least 110% of an included angle of the pole tips and a packing factor of at least 60%.

135. The method of claim 130 including forming the field coils to have an included angle of at least 125% of an included angle of the pole tips and a packing factor of at least 60%.

136. The method of claim 130 including forming the field coils to have an included angle of at least 145% of an included angle of the pole tips and a packing factor of at least 60%.

137. The method of claim 130 including forming the field coils to have an included angle of at least 155% of an included angle of the pole tips and a packing factor of at least 60%.

138. The method of claim 130 including forming the field coils to have an included angle of at least 110% of an included angle of the pole tips and a packing factor of at least 70%.

139. The method of claim 130 including forming the field coils to have an included angle of at least 125% of an included angle of the pole tips and a packing factor of at least 70%.

140. The method of claim 130 including forming the field coils to have an included angle of at least 145% of an included angle of the pole tips and a packing factor of at least 70%.

141. The method of claim 130 including forming the field coils to have an included angle of at least 155% of an included angle of the pole tips and a packing factor of at least 70%.

142. An electric motor of a given frame size having increased power compared to a conventional needle wound motor of the same frame size, comprising:

a. a stator having pole pieces on which field coils are disposed and return path pieces mated to the pole pieces, the field coils extending beyond pole tips of the pole pieces on which they are disposed, the stator having an outside diameter;

b. an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator; and

c. the field coils formed to provide the motor with a maximum power output at a desired speed that is at least ten percent greater than a maximum power output at the desired speed of the conventional needle wound motor of the same frame size.

143. The motor of claim 142 wherein the electric motor has a 55 mm frame size and a maximum power output at 38,000 rpm of at least 1000 watts.

144. The motor of claim 142 wherein the electric motor has a 59 mm frame size and a maximum power output at 38,000 rpm of at least 1250 watts.

145. The motor of claim 142 wherein the electric motor has a 59 mm frame size and a maximum power output at 38,000 rpm of at least 1600 watts.

146. The motor of claim 142 wherein the field coils have an included angle of at least 110% of an included angle of the pole tips and a packing factor of at least 60%.

147. The motor of claim 142 wherein the field coils have an included angle of at least 125% of an included angle of the pole tips and a packing factor of at least 60%.

148. The motor of claim 142 wherein the field coils have an included angle of at least 145% of an included angle of the pole tips and a packing factor of at least 60%.

149. The motor of claim 142 wherein the field coils have an included angle of at least 155% of an included angle of the pole tips and a packing factor of at least 60%.

150. The motor of claim 142 wherein the field coils have an included angle of at least 110% of an included angle of the pole tips and a packing factor of at least 70%.

151. A hand-held power tool, comprising:

a. a housing;

b. a motor of a given frame size disposed in the housing, the motor having increased power compared to a conventional needle wound motor of the same frame size, the motor including;

i. a stator having pole pieces on which field coils are disposed and return path pieces mated to the pole pieces, the field coils extending beyond pole tips of the pole pieces on which they are disposed, the stator having an outside diameter;

ii. an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator; and

iii. the field coils formed to provide the motor with a maximum power output at a desired speed that is at least ten percent greater than a maximum power output at a desired speed of the conventional needle wound motor of the same frame size.

152. The power tool of claim 151 wherein the electric motor has a 55 mm frame size and a maximum power output at 38,000 rpm of at least 1000 watts.

153. The power tool of claim 151 wherein the electric motor has a 59 mm frame size and a maximum power output at 38,000 rpm of at least 1250 watts.

154. The power tool of claim 151 wherein the electric motor has a 59 mm frame size and a maximum power output at 38,000 rpm of at least 1600 watts.

155. The power tool of claim 151 wherein the field coils have an included angle of at least 110% of an included angle of the pole tips and a packing factor of at least 60%.

156. The power tool of claim 151 wherein the field coils have an included angle of at least 125% of an included angle of the pole tips and a packing factor of at least 60%.

157. The power tool of claim 151 wherein the field coils have an included angle of at least 145% of an included angle of the pole tips and a packing factor of at least 60%.

158. The power tool of claim 151 wherein the field coils have an included angle of at least 155% of an included angle of the pole tips and a packing factor of at least 60%.

159. The power tool of claim 151 wherein the field coils have an included angle of at least 110% of an included angle of the pole tips and a packing factor of at least 70%.

172. A method of making an electric motor, comprising:

a. forming field coils to a predetermined shape including winding them with at least two different sizes of wire;

b. forming pole pieces and return path pieces;

c. placing the field coils on the pole pieces after forming them to the predetermined shape;

d. mating the pole pieces and return path pieces after placing the field coils on the pole pieces to form a stator having an outside diameter; and

e. placing an armature in the stator.

173. An electric motor, comprising:

a. a stator having pole pieces on which field coils having windings of at least two different sizes of wires are disposed and return path pieces mated to the pole pieces; and

b. an armature.

174. A hand-held power tool, comprising:

a. a housing; and

b. a motor disposed in the housing, the motor including;

i. a stator having pole pieces on which field coils having windings of at least two different sizes of wire are disposed and return path pieces mated to the pole pieces, the stator having an outside diameter; and

ii. an armature.