Abnormality detection method for electromagnetic relay, abnormality detection circuit for electromagnetic relay, and abnormality detection system

Patent metadata

Field	Value
Publication number	US-2016358732-A1
Application number	US-201415113366-A
Country	US
Kind code	A1
Filing date	Aug 5, 2014
Priority date	Feb 27, 2014
Publication date	Dec 8, 2016
Grant date	—

Abstract

An abnormal operation of a movable contact is correctly detected. The abnormal operation of the movable contact ( 9 ) to the fixed contact ( 10 ) is detected based on at least one of a separation transient response signal of a coil current passed through the excitation coil ( 6 ) during the supply of a separation pulse signal and an attraction transient response signal of the coil current during the supply of an attraction pulse signal.

First claim

1 . An abnormality detection method for electromagnetic relay in which a movable contact and a fixed contact are closed or opened by an electromagnetic force generated in accordance with supply or cutoff of a current to an excitation coil,
wherein an abnormal operation of the movable contact to the fixed contact is detected based on at least one of a first transient response signal of a coil current passed through the excitation coil during the supply of a first detection pulse signal in a state of not supplying an operation signal to operate the movable contact relative to the fixed contact and a second transient response signal of the coil current during the supply of a second detection pulse signal in a state of supplying the operation signal.

2 . The abnormality detection method for electromagnetic relay according to claim 1 , wherein the first transient response signal is generated by applying the first detection pulse signal to a switching element that supplies the coil current to the excitation coil,
the second transient response signal is generated by applying the second detection pulse signal to the switching element, a period of the first detection pulse signal is sufficiently shorter than that of the first transient response signal, and a period of the second detection pulse signal is sufficiently shorter than that of the second transient response signal.

3 . The abnormality detection method for electromagnetic relay according to claim 1 , wherein the abnormal operation of the movable contact to the fixed contact is detected based on a threshold set in accordance with the first transient response signal and the second transient response signal.

4 . The abnormality detection method for electromagnetic relay according to claim 3 , wherein the abnormal operation of the movable contact to the fixed contact is detected based on a time width corresponding to a magnitude relationship between the threshold and a third transient response signal of the coil current during the supply of a third detection pulse signal.

5 . The abnormality detection method for electromagnetic relay according to claim 3 , wherein the abnormal operation of the movable contact to the fixed contact is detected based on the threshold, a third transient response signal of the coil current during the supply of a third detection pulse signal, and a clock time at which a difference between the first transient response signal and the second transient response signal is maximized, or the abnormal operation is detected based on a sign of an integrated value obtained from the third transient response signal and the threshold.

6 . The abnormality detection method for electromagnetic relay according to claim 3 , wherein the threshold is updated by repeatedly generating the first transient response signal is repeatedly generated in each predetermined time, by generating the first transient response signal in response to an on-signal externally supplied to operate the movable contact relative to the fixed contact, or by repeatedly generating the second transient response signal in each predetermined time.

7 . The abnormality detection method for electromagnetic relay according to claim 1 , wherein a duty of the first detection pulse signal is controlled such that a difference between a current value of the first transient response signal before the supply of the first detection pulse signal and a target value of a current of the first transient response signal during the supply of the first detection pulse signal is kept constant, or a duty of the second detection pulse signal is controlled such that a difference between a current value of the second transient response signal before the supply of the second detection pulse signal and a target value of a current of the second transient response signal during the supply of the second detection pulse signal is kept constant.

8 . The abnormality detection method for electromagnetic relay according to claim 3 , wherein the threshold is set, and the abnormal operation of the movable contact to the fixed contact is detected based on the threshold and a third transient response signal of the coil current during the supply of a third detection pulse signal after elapse of a predetermined time.

9 . The abnormality detection method for electromagnetic relay according to claim 3 , wherein the second transient response signal is generated, and a determination that an abnormality occurs in the operation of the electromagnetic relay when a value of another second transient response signal generated by supplying the second detection pulse signal after elapse of a predetermined time exceeds the threshold.

10 . The abnormality detection method for electromagnetic relay according to claim 1 , wherein the movable contact is operated relative to the fixed contact by applying the operation signal to a first switching element, the first switching element being connected in parallel with a second switching element configured to supply the coil current to the excitation coil with respect to the excitation coil,
the first switching element is turned off, and the second detection pulse signal is applied to the switching element to generate the second transient response signal.

11 . An abnormality detection circuit for electromagnetic relay in which a movable contact and a fixed contact are closed or opened by an electromagnetic force generated in accordance with supply or cutoff of a current to an excitation coil, the abnormality detection circuit comprising
a control circuit configured to detect an abnormal operation of the movable contact to the fixed contact based on at least one of a first transient response signal of a coil current passed through the excitation coil during the supply of a first detection pulse signal in a state of not supplying an operation signal to operate the movable contact relative to the fixed contact and a second transient response signal of the coil current during the supply of a second detection pulse signal in a state of supplying the operation signal.

12 . An abnormality detection system comprising: an electromagnetic relay in which a movable contact and a fixed contact are closed or opened by an electromagnetic force generated in accordance with supply or cutoff of a current to an excitation coil; and
an abnormality detection circuit configured to detect an abnormal operation of the movable contact to the fixed contact based on at least one of a first transient response signal of a coil current passed through the excitation coil during the supply of a first detection pulse signal in a state of not supplying an operation signal to operate the movable contact relative to the fixed contact and a second transient response signal of the coil current during the supply of a second detection pulse signal in a state of supplying the operation signal.

13 . An abnormality detection method for electromagnetic relay in which a movable contact and a fixed contact are closed or opened by an electromagnetic force generated in accordance with supply or cutoff of a current to an excitation coil,
wherein an abnormal operation of the movable contact to the fixed contact is detected based on at least one of a first transient response signal of a coil current passed through the excitation coil during the supply of a first detection pulse signal in a non-operation state of the movable contact relative to the fixed contact and a second transient response signal of the coil current during the supply of a second detection pulse signal in an operation state of the movable contact relative to the fixed contact.

14 . An abnormality detection ci

Assignees

• Omron Tateisi Electronics Co

Inventors

• Nishio Norikazu

Classifications

• G01R31/3278

  of relays, solenoids or reed switches (measuring contact resistance G01R27/205; high voltage magnetic switches G01R31/3271, G01R31/333; testing electric windings G01R31/72; monitoring of fail safe circuits H01H47/002) · CPC title

• H01H47/002 Primary

  Monitoring or fail-safe circuits · CPC title

• H01H47/04

  for holding armature in attracted position, e.g. when initial energising circuit is interrupted; for maintaining armature in attracted position, e.g. with reduced energising current {(with switching regulator H01H47/325)} · CPC title

• H01H2047/003

  Detecting welded contacts and applying weld break pulses to coil · CPC title