abc_de
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Measured? or expected?Line voltage is 90v phase to phase
I guess not. It depends on the hight and duration of the overvoltage signal.I have not add mov for 150v phase to phase input of power supply does it will solve my problem
A resistor is no fuse. So a fuse has defined trip characteristic. It should avoid explosion and fire. But it will not keep capacitor and resistor alive.And i also thinking to add 1amp 250vac fuse instead of 10ohm 1/2w resistor
Yes, but will help to prevent pcb burning during capacitor/ resistorIt should avoid explosion and fire. But it will not keep capacitor and resistor alive
Capacitor is rated for 275vaccapacitor is not rated for the applied voltage
I just using +5v for mcu, IR sensor, proximity sensor, MOC3083 Driver.The other factor not mentioned is what the supply is used for. For example, is it possible the negative output is getting connected to earth or one of the other phases, that would connect the resistor and one of the diodes directly across high voltage.
Brian.
But when i check on motor terminal there was no spike during turn on and off i am using zero crossing detected opto triac driver.the triac switching puts notches on the mains, these higher frequencies go straight thru the 2.2uF cap and cook the resistor, if there are other noises on the mains from other equipments this will make it worse. this is a well known issue for cap dropper psu's ....
But when i check on motor terminal there was no spike during turn on and off i am using zero crossing detected opto triac driver.
Right unexpected energy may be cause of burn
Mov or tvs diode may help in this case
Transformer step down 3phase 380v to 90v for motor Iout:5amp @90vacHi,
You say there is a transformer in front of it.
What size /watts is it?
When you switch the transformer off while the motor is off (unloaded) then all the energy stored in the transformer may cause high energetic peaks.
Depending at witch time of the sine you switch off.
When measuring with a scope: be careful not to kill your scope.
Klaus
You talk about motor swithiching, but I asked for transformer switching.Transformer step down 3phase 380v to 90v for motor Iout:5amp @90vac
Zero crossing driver always switch on after zero crossing of sine wave and after switch off triac conduct for following half cycle.
Thats why i choose zero crossing driver instead of random phase triac driver
Transformer step down 3phase 380v to 90v for motor Iout:5amp @90vac
Zero crossing driver always switch on after zero crossing of sine wave and after switch off triac conduct for following half cycle.
Thats why i choose zero crossing driver instead of random phase triac driver
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