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US 4,307,775 AGranted
Current monitoring control for electrically powered devices
AssigneeThe Trane Company
InventorsJames F. Saunders, Robert E. Krocker
Life of this patent
Estimating the term…
Abstract
Apparatus and method for controlling one or more electrically powered devices. A control for a temperature conditioning system is shown which is operative to monitor the electrical current supplied to component devices, i.e., compressors, auxiliary heating elements, indoor fan, and outdoor fan; and to cause an indicator means to indicate that one or more of the devices has failed to operate in a manner consistent with the controlled status of the system. If a failure is detected, control means are operative to lock out one or more of the devices from operation.
Claims31
Apparatus for controlling one or more electrically powered devices comprising
- a. a current sensing transducer for producing a signal proportional to the magnitude of electrical supply current to said devices;
- b. indicator means for indicating that one or more of said devices has failed;
- c. control means for energizing and de-energizing the one or more devices, thereby determining their controlled status, connected to receive and monitor the signal produced by the current sensing transducer, and including means for comparing the magnitude of successively monitored values of the signal, thereby responding to relative changes in the magnitude of said supply current, such that the control means are operative to cause the indicator means to indicate that one or more of the devices has failed, if one of the following conditions occurs:
- i. the magnitude of the signal proportional to the supply current does not substantially increase over the preceding value monitored by the control means when said control means attempt to energize one or more of the devices;
- ii. the magnitude of the signal proportional to the supply current does not substantially decrease from the preceding value monitored by the control means when said control means attempt to de-energize one or more devices;
- iii. the magnitude of the signal proportional to the supply current decreases from the preceding value monitored by the control means independently of the control means effecting a change in the controlled status of said one or more devices;
- or
- iv. the magnitude of the signal proportional to the supply current increases over the preceding value monitored by the control means independently of the control means effecting a change in the controlled status of said one or more devices.
5 more elements
Apparatus for controlling one or more electrically powered devices comprising
- a. a current sensing transducer for producing a signal proportional to the magnitude of electrical supply current to said devices;
- b. indicator means for indicating that one or more of said devices has failed;
- c. control means for energizing the one or more devices, thereby determining their controlled status, connected to receive and monitor the signal produced by the current sensing transducer, and including means for comparing the magnitude of successively monitored values of the signal, thereby responding to relative changes in the magnitude of said supply current, such that the control means are operative to cause the indicator means to indicate that one or more of the devices has failed, if the magnitude of the signal proportional to the supply current does not increase over the preceding value monitored by the control means when said control means attempt to energize one or more of the devices.
Apparatus for controlling one or more electrically powered devices comprising
- a. a current sensing transducer for producing a signal proportional to the magnitude of electrical supply current to said devices;
- b. indicator means for indicating that one or more of said devices has failed;
- c. control means for energizing and de-energizing the one or more devices, thereby determining their controlled status, connected to receive and monitor the signal produced by the current sensing transducer, and including means for comparing the magnitude of successively monitored values of the signal, thereby responding to the relative changes in the magnitude of said supply current, such that the control means are operative to cause the indicator means to indicate that one or more of the devices has failed, if the magnitude of the signal proportional to the supply current does not decrease from the preceding value monitored by the control means when said control means attempt to de-energize one or more of the devices.
Apparatus for controlling one or more electrically powered devices comprising
- a. a current sensing transducer for producing a signal proportional to the magnitude of electrical supply current to said devices;
- b. indicator means for indicating that one or more of said devices has failed;
- c. control means for energizing and de-energizing the one or more devices, thereby determining their controlled status, connected to receive and monitor the signal produced by the current sensing transducer, and including means for comparing the magnitude of successively monitored values of the signal, thereby responding to relative changes in the magnitude of said supply current, such that the control means are operative to cause the indicator means to indicate that one or more of the devices has failed, if the magnitude of the signal proportional to the supply current decreases from the preceding value monitored by the control means independently of the control means effecting a change in the controlled status of said one or more devices.
Apparatus for controlling one or more electrically powered devices comprising
- a. a current sensing transducer for producing a signal proportional to the magnitude of electrical supply current to said devices;
- b. indicator means for indicating that one or more of said devices has failed;
- c. control means for energizing and de-energizing the one or more devices, thereby determining their controlled status, connected to receive and monitor the signal produced by the current sensing transducer, and including means for comparing the magnitude of successively monitored values of the signal, thereby responding to relative changes in the magnitude of said supply current, such that the control means are operative to cause the indicator means to indicate that one or more of the devices has failed, if the magnitude of the signal proportional to the supply current increases over the preceding value monitored by the control means independently of the control means effecting a change in the controlled status of said one or more devices.
A method for controlling one or more electrically powered devices comprising the steps of
- a. sensing the magnitude of electrical supply current to said devices and producing a signal proportional to said magnitude;
- b. receiving and monitoring the signal proportional to the magnitude of said supply current;
- c. comparing the magnitude of successively monitored values of the signal, thereby responding to relative changes in the magnitude of the current;
- d. energizing and de-energizing the one or more devices, thereby determining their controlled status;
- and
- e. effecting an indication of failure of one or more of the devices if one of the following conditions should occur:
- i. the magnitude of the signal proportional to the supply current does not substantially increase over the immediately preceding monitored value when an attempt is made to energize one or more of the devices;
- ii. the magnitude of the signal proportional to the supply current does not substantially decrease from the immediately preceding monitored value when an attempt is made to de-energize one or more of the devices;
- iii. the magnitude of the signal proportional to the supply current decreases from the immediately preceding monitored value independently of a controlled change in the controlled status of said one or more devices;
- or
- iv. the magnitude of the signal proportional to the supply current increases over the immediately preceding monitored value independently of a controlled change in the controlled status of said one or more devices.
8 more elements
A method for controlling one or more electrically powered devices comprising the steps of
- a. sensing the magnitude of electrical supply current to said devices and producing a signal proportional to said magnitude;
- b. receiving and monitoring the signal proportional to the magnitude of said supply current;
- c. comparing the magnitude of successively monitored values of the signal, thereby responding to relative changes in the magnitude of the current;
- d. energizing and de-energizing the one or more devices, thereby determining their controlled status;
- and
- e. effecting an indication of failure of one or more of the devices if the magnitude of the signal proportional to the supply current does not substantially decrease from the immediately preceding monitored value when an attempt is made to de-energize one or more of the devices.
3 more elements
A method for controlling one or more electrically powered devices comprising the steps of
- a. sensing the magnitude of electrical supply current to said devices and producing a signal proportional to said magnitude;
- b. receiving and monitoring the signal proportional to the magnitude of said supply current;
- c. comparing the magnitude of successively monitored values of the signal, thereby responding to relative changes in the magnitude of the current;
- d. energizing and de-energizing the one or more devices, thereby determining their controlled status;
- and
- e. effecting an indication of failure of one or more of the devices if the magnitude of the signal proportional to the supply current does not substantially decrease from the immediately preceding monitored value when an attempt is made to de-energize one or more of the devices.
3 more elements
A method for controlling one or more electrically powered devices comprising the steps of
- a. sensing the magnitude of electrical supply current to said devices and producing a signal proportional to said magnitude;
- b. receiving and monitoring the signal proportional to the magnitude of said supply current;
- c. comparing the magnitude of successively monitored values of the signal, thereby responding to relative changes in the magnitude of the current;
- d. energizing and de-energizing the one or more devices, thereby determining their controlled status;
- and
- e. effecting an indication of failure of one or more of the devices if the magnitude of the signal proportional to the supply current decreases from the immediately preceding monitored value independently of a controlled change in the controlled status of said one or more devices.
3 more elements
A method for controlling one or more electrically powered devices comprising the steps of
- a. sensing the magnitude of electrical supply current to said devices and producing a signal proportional to said magnitude;
- b. receiving and monitoring the signal proportional to the magnitude of said supply current;
- c. comparing the magnitude of successively monitored values of the signal, thereby responding to relative changes in the magnitude of the current;
- d. energizing and de-energizing the one or more devices, thereby determining their controlled status;
- and
- e. effecting an indication of failure of one or more of the devices if the magnitude of the signal proportional to the supply current increases over the immediately preceding monitored value independently of a controlled change in the controlled status of said one or more devices.
3 more elements
Apparatus for controlling a temperature conditioning system including a plurality of electrically powered devices, said apparatus comprising
- a. a current transformer having:
- a primary winding connected in series between one or more of the devices and a source of electrical power supply, and
- a secondary winding which produces an electrical signal that is proportional in magnitude to that of the total supply current flowing to said one or more devices;
- b. indicator means for indicating that one or more of the devices having current supplied through the primary winding on the current transformer has failed;
- c. switching means for connecting and disconnecting each of the devices to and from the source of electrical power supply in response to a control signal;
- d. control means connected to transmit the control signal to the switching means, for selectively energizing and de-energizing the one or more devices thereby determining their controlled status, and connected to receive and to periodically monitor the signal produced by the secondary winding of the current transformer, said control means including means for retaining the magnitude of the current transformer secondary signal previously monitored until after that signal is again periodically monitored;
- and means for comparing the magnitudes of the previously retained signal and the present signal indicative of the supply current, as it is successively monitored, whereby the control means are further operative to cause the indicator means to indicate that one or more of the devices has failed, if one or more of the following conditions occurs:
- i. the magnitude of the supply current does not substantially increase when said control means attempt to energize one or more of the devices;
- ii. the magnitude of the supply current does not substantially decrease when said control means attempt to de-energize one or more of the devices;
- iii. the magnitude of the supply current decreases independently of the control means transmitting a control signal to the switching means;
- or
- iv. the magnitude of the supply current increases independently of the control means transmitting a control signal to the switching means.
9 more elements
A method for controlling a temperature conditioning system including a plurality of electrically powered devices, and a current transformer with a primary winding connected in series between one or more of the devices and a source of electrical power supply and a secondary winding which produces an electrical signal that is proportional in magnitude to that of the total supply current flowing to said one or more devices, comprising the steps of:
- a. receiving and periodically monitoring the electrical signal produced by the current transformer secondary winding;
- b. connecting and disconnecting each of the devices to and from the source of electrical power supply to selectively energize and de-energize the devices to meet a temperature conditioning demand, thereby determining their controlled status;
- c. retaining the magnitude of the current transformer secondary winding signal previously monitored until after that signal is again periodically monitored;
- d. comparing the magnitudes of the previously retained signal and the present signal indicative of the total supply current, as it is successively monitored;
- and
- e. effecting an indication of failure of one or more of the devices if one or more of the following conditions should occur:
- i. the magnitude of the supply current does not substantially increase when said control means attempt to energize one or more of the devices;
- ii. the magnitude of the supply current does not substantially decrease when said control means attempt to de-energize one or more of the devices;
- iii. the magnitude of the supply current decreases independently of the control means effecting a change in the controlled status of said one or more devices;
- or
- iv. the magnitude of the supply current increases independently of the control means effecting a change in the controlled status of said one or more devices.
8 more elements
Dependencies are inferred from the claim text.