Apparatus and method for starter RPM detection
First Claim
1. A tester for vehicle engine starter motors, comprising:
- a mechanical clamping apparatus to restrain a motor under test from rotating during startup and slowdown;
an electrical circuit to apply power to the starter motor;
a detector circuit to sense the rate at which the starter motor spins; and
a display to report the detected spin rate.
1 Assignment
0 Petitions
Accused Products
Abstract
An engine starter motor tester applies power to a motor under test at the level normally applied while that motor is installed in a vehicle and monitors the ripple in the driving current. The ripple rate, scaled by the number of windings used in the construction of the motor, provides a direct reading of the shaft speed of the unloaded motor. This number allows a valid inference concerning the state of health of the motor, and is more certain than an estimate for an unloaded motor based on operator experience and motor “sound”. A complete test apparatus includes a stored lookup table, allowing the user to key in a product brand and model number and read directly both the RPM and the test apparatus'"'"'s rating of the motor under test, expressed in terms such as percentage of life remaining.
-
Citations
27 Claims
-
1. A tester for vehicle engine starter motors, comprising:
-
a mechanical clamping apparatus to restrain a motor under test from rotating during startup and slowdown;
an electrical circuit to apply power to the starter motor;
a detector circuit to sense the rate at which the starter motor spins; and
a display to report the detected spin rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. An apparatus for performing vehicle engine starter motor testing tasks, comprising:
-
means for applying suitable DC power to vehicle engine starter motors;
means for applying control signals to starter motors;
means for sensing the current level drawn by said starter motors;
means for detecting in the sensed starter motor current level pulsation attributable to addition and removal of individual armature windings from the power circuit as the motor'"'"'s brushes make and break contact with individual segments of the motor'"'"'s commutator;
means for converting detected pulses into a pulse rate indication; and
means for displaying as an output the sensed and scaled RPM of the starter motor under test. - View Dependent Claims (21, 22, 23)
-
-
24. A method for performance of starter motor testing tasks, comprising the following steps:
-
converting incoming AC input power to DC at the range of levels of voltage and current required for operating vehicle engine starter motors;
applying the DC so developed to the starter motor under test;
sensing the average and transient current of the power applied to the starter motor under test;
converting the ripples in the sensed current level to a ripple rate;
scaling the ripple rate signal based on the motor design to yield an effective motor armature RPM value;
displaying the effective RPM value in human-readable form; and
displaying a summary indication of the condition of the starter motor under test. - View Dependent Claims (25, 26)
-
-
27. A system for performing starter motor testing tasks, comprising:
-
a power supply configured to convert incoming AC power to DC at a range of levels suitable for representative vehicle engine starter motors;
a power application arrangement to apply DC at a suitable level to a vehicle engine starter motor;
a sense circuit configured to detect the current draw while the starter motor is running at an applied voltage at which it was intended to be operated;
a differentiation circuit configured to sense ripple in the sensed motor current and convert that signal to a motor winding rate;
a scaler circuit configured to correct the detected rate according to the properties of the starter motor under test, including number of rotor windings; and
an output section configured to provide an interface to a user, particularly providing an RPM indication.
-
Specification