US 11,988,713 B2
Contact signal acquisition circuit for on-site on-line check of gas density relay
Wei Zeng, Shanghai (CN); Min Chang, Shanghai (CN); Xiaobeng Huang, Shanghai (CN); Haiming Liao, Shanghai (CN); Haisheng Jin, Shanghai (CN); and Enlin Wang, Shanghai (CN)
Assigned to Shanghai Roye Electric Co., Ltd., Shanghai (CN)
Appl. No. 17/640,774
Filed by SHANGHAI ROYE ELECTRIC CO., LTD., Shanghai (CN)
PCT Filed Aug. 26, 2020, PCT No. PCT/CN2020/111253
§ 371(c)(1), (2) Date Mar. 4, 2022,
PCT Pub. No. WO2021/043041, PCT Pub. Date Mar. 11, 2021.
Claims priority of application No. 201910830210.6 (CN), filed on Sep. 4, 2019.
Prior Publication US 2022/0308112 A1, Sep. 29, 2022
Int. Cl. G01R 31/327 (2006.01); G01N 9/00 (2006.01); H01H 35/24 (2006.01)
CPC G01R 31/3274 (2013.01) [G01N 9/00 (2013.01); H01H 35/24 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A contact signal acquisition circuit for online checking a gas density relay on site, comprising a first connecting circuit and a second connecting circuit, the first connecting circuit connecting a contact of the gas density relay to a contact signal control loop, and the second connecting circuit connecting the contact of the gas density relay to a contact signal sampling interface of an online check device, wherein
in a non-checking state, the contact is a normally open density relay, the second connecting circuit is disconnected or broken, and the first connecting circuit is closed; and in a checking state, the first connecting circuit is disconnected, and the second connecting circuit is connected, so as to connect the contact of the gas density relay to the contact signal sampling interface of the online check device; alternatively,
in a non-checking state, the contact is a normally closed density relay, the second connecting circuit is disconnected or broken, and the first connecting circuit is closed; and in a checking state, the contact signal control loop is closed, the contact of the gas density relay is disconnected from the contact signal control loop, and the second connecting circuit is connected, so as to connect the contact of the gas density relay to the contact signal sampling interface of the online check device,
wherein the second connecting circuit further comprises a photocoupler and a resistor, the photocoupler comprising a light-emitting diode and a phototransistor, the light-emitting diode being connected in series to the contact of the gas density relay to form a closed loop, an emitter of the phototransistor being grounded, a collector of the phototransistor being connected to the online check device, and the collector of the phototransistor being further connected to a power supply by means of the resistor;
when the contact is closed, the closed loop is energized, the light-emitting diode emits light, the phototransistor is switched on by the light, and the collector of the phototransistor outputs a low level; and
when the contact is disconnected, the closed loop is disconnected, the light-emitting diode does not emit light, the phototransistor is switched off, and the collector of the phototransistor outputs a high level.