Indirect current monitoring via voltage and impedance monitoring

• US 4,514,619 A
• Filed: 09/30/1982
• Issued: 04/30/1985
• Est. Priority Date: 09/30/1982
• Status: Expired due to Term

• Current Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Kugelman, Michael M.
• Primary Examiner(s): PASCHALL, MARK H
• Application Number:
  US06/431,951
• Time in Patent Office: 943 Days
• Field of Search: 323/283, 323/235, 323/319, 219/494, 219/497, 219/202, 219/203, 219/501, 219/483, 219/485, 219/486, 219/490, 219/492, 219/493, 244/134 R, 244/134 D, 364/483, 324/76 R, 324/126, 307/39-41
• US Class Current: 219/483
• CPC Class Codes: B64D 15/14 controlled cyclically along length of surface
• CPC Class Codes: G05D 23/19 characterised by the use of electric means G05D23/1393 takes precedence
• CPC Class Codes: H05B 1/0236 for vehicles
• CPC Class Codes: H05B 2214/02 Heaters specially designed for de-icing or protection against icing

Abstract

Electrical circuitry for monitoring the current flow through resistance elements on the leading edge of an aircraft wing or horizontal stabilizer. The resistance elements are individually and sequentially activated for heating to thereby effect a de-icing or anti-icing function. The non-activated elements are sensed by the circuitry to determine inferentially if there is a predetermined current flow through the heating elements to achieve the intended de-icing or anti-icing function.

Claims

1. A circuit for monitoring electrical current from a source of power along lead line means to a load means comprising

switch means in said lead line means being sequentially operative from a first mode wherein load current may flow from the source of power to said load means, to a second mode wherein test current may flow along another line means for determining whether the impedance of load is the correct magnitude,

impedance measurement means operatively coupled with said switch means for determining impedance of the load means when said switch means is in the second mode,

voltage measurement means for determining the voltage present at the load means,

current determining means operatively coupled with said impedance measurement means and said voltage measurement means for determining load current being delivered to the load means as a function of signals received from said impedance measurement means and said voltage measurement means,

switching control means for periodically changing said switch means from the first mode to the second mode and for periodically rendering operative said impedance measurement means, voltage measurement means and current determining means, and

output means activated from said current determining means for response to whether or not the load means are being operated in a predetermined manner.

2. A circuit for monitoring electrical current from a source of power along lead lines to a plurality of loads comprising

a plurality of switch means, one in each of the lines extending from the source of power to the plurality of loads, each said switch means being sequentially operative from a first mode, wherein load current may flow from the source of power to each of the plurality of loads, to a second mode wherein test current may flow along another line for determining whether the impedance of the plurality of load is the correct magnitude,

impedance measurement means operatively coupled with each of said switch means for determining impedance of each of the plurality of loads when the switch means to which it is operatively coupled is in its second mode,

voltage measurement means for determining the voltage present at the plurality of loads,

current determining means operatively coupled with the impedance measurement means and the voltage measurement means for determining load current being delivered to the plurality of loads as a function of signals received from the impedance measurement means and voltage measurement means,

switching control means for periodically and sequentially changing each of said switch means from the first mode to the second mode and also for periodically rendering operative the impedance measurement means, voltage measurement means and current determining means, and

output means activated from the current determining means for response to whether or not the load means are being operated in a predetermined manner.

3. A circuit for monitoring electrical current comprising

a plurality of electrical resistance elements,

a source of power along lead lines coupling said source of power to each of said resistance elements,

a plurality of switch means, one in each of said lines extending from said source of power to said plurality of elements, each said switch means being sequentially operative from a first mode, wherein load current may flow from said source of power to each of said plurality of elements, to a second mode wherein test current may flow along a second line means for determining whether the impedance of the plurality of elements is the correct magnitude,

impedance measurement means coupled by said second line means with each of said switch means for determining impedance of each of said plurality of elements when the switch means to which it is operatively coupled is in its second mode,

voltage measurement means for determining the voltage present at said plurality of elements,

current determining means operatively coupled with the impedance measurement means and the voltage measurement means for determining load current being delivered to said plurality of elements as a function of signals received from the impedance measurement means and voltage measurement means,

switching control means for periodically and sequentially changing each of said switch means from the first mode to the second mode and also for periodically rendering operative the impedance measurement means, voltage measurement means and current determining means, and

output means activated from the current determining means for response to whether or not said plurality of elements are being operated in a predetermined manner.