Measures for the protection of explosion-proof electric valves varying load equipment
In the past for motor protection method is to use a fuse, overcurrent relay, thermal relay, thermostat, etc. , but these methods all have advantages and disadvantages.
The variable load of explosion-proof electric valve device, is not absolutely reliable measures for the protection of.
So we must take various combinations, induces has two kinds: one is the increase or decrease of the motor input current judgment;
The second is the motor itself heating situations.
These two approaches, both the heat capacity of the given time allowance to consider motor.
Electric gate valves, electric valve explosion-proof electric three-way ball valve, usually on the basis of the overload protection method is: the continuous operation of motor or inching operation over load protection, use a thermostat;
The protection of motor blocked, the thermal relay;
For short circuit accident, adopt the fuse or over-current relay.
Late due to the innovation of system development, domestic explosion-proof electric valve without big technology innovation, poor controllability and low measurement precision, large amount of maintenance, etc.
At present there are 20 of explosion-proof electric valve in use -
250000 units have been in the stage of change.
And the original domestic explosion-proof electric valve has to replace.
Domestic explosion-proof electric valve mechanical life in 15 -
25 years, motor life 8 -
For 10 years.
In addition, there are 3 -
Explosion-proof electric valve electric control part of the 50000 sets of import have different problems need to be solved.