- Jul 22, 2010 -
How to solve the brake open delay time of cranes？
Variable frequency control in the use of bridge crane, 35+50+35+5T, electromagnetic brake motor brake.
Brake open delay time is too long (about 2 seconds, the normal should be 0.2 seconds)
The solution process:
At about 2 in the morning, the night crew received the operator phone, and the A hook did not move. To check the traffic on the hook, the brake temperature is high, and there is a strong smell of burnt, the brake gap is larger than 1mm. Then replace the brake solenoid, adjust the brake clearance is 0.7mm. Open the A hook, found 2 seconds to open the brake motor rotation after the serious delay. So check the A hook Inverter Parameters of 6.16 brake open the lowest frequency of 6.17 0.1HZ, the lowest frequency of 6.18 0.1HZ off the brake, brake control delay of 0. seconds, 6.19 brake open delay of 0.2 seconds, compared with B hook Inverter Parameters exactly the same. The problem of the parameter of frequency converter is eliminated. After replacing the brake rectifier module ESD141 and A converter hook phenomenon still exists. At daybreak, the day shift staff has to work, so the discussion. The night shift staff introduced the failure phenomenon, the focus on why so long on the brake time delay. The day will be opened step by step with the brake process with written on paper, carries on the analysis step by step.
1, K1 inverter power RDY contactor
2, the remote control signal to rise, the motor frequency converter M1 is to continually
3, when the output frequency to 0.1HZ inverter A1 control board in 0.2 seconds after the 23-24 normally open pull K7 brake relay coil gets electricity to attract
4, K7 pull brake rectifier module ESD141 full wave rectifier, the output of 341V DC to make electric brake coil, the electromagnetic force under the action of the brake open.
5, brake open after 0.3 seconds, the K7 delay open the normally closed contact action, ESD141 into the half wave rectifier, the output of 171V DC, while the brake remains open.
This brake open.
1, frequency converter parameter
2, ESD141's full wave rectifying voltage 341V and half wave 171V DC are normal
Continue checking on the hot traffic. It is found that the inverter parameters are correct. The half wave rectification 171V is correct. The full wave 341V can not be detected due to 0.3 seconds of reaction time. Boring measurement ESD141 line end voltage U12=402V, U13=400V, U23=0V, look at the drawings, ha ha smile, the original line is wrong! Adjust the 12 phase order, open the A hook, normal. The moment, open voltage for full wave voltage, phase voltage of 0.9 times around 360V, phase voltage after brake maintain voltage is 0.45 times of about 180V or so, in summary: instantly open voltage for full wave voltage, phase voltage of 0.9 times around 360V, after the brake electric phase voltage pressure is 0.45 times about is about 180V, that can withstand voltage transient 360V? The current electromagnetic brake torque is high pressure absorption, low voltage maintenance.