Letching WaveGuide Switch Failure

Hello,

A waveguide latching switch failed twice , the motor coil became short circuit.
I am using stable 24V supply to feed the motor.
No visible circuit problem Accept that for 1 Msec both Control input get the 24V during Change command.
Can this be the culprit?
Or may be a cuurent spike during switching?

Geri-l

Hi,

What values can we see from your post?
--> 24V, 1ms, any motor, any relay

And you ask us if current can be the problem.

How can we know? So the only answer can be: yes, current can be the problem

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If you need a more precise answer you need to give us more informations:
Motor type, relay type, complete circuit, power supply, control circuit timing....

Klaus

assuming it is a purely passive coil you are driving, to short out a magnetic wirewound coil, you would need to put a LOT of current into it so that it heated up and the insulation fried. So, have you measured the CURRENT while it is transitioning?

It might be wise to put a current limiting resistor, maybe 1 ohm or so, in series with the coil.

voltage spikes are certainly possible, since you are driving a big L with a step current, and when that current turns off there will be a big voltage spike as the magnetic field collapses. but, they only will effect the driver electronics, and can usually be easily fixed with a capacitor across the coil or a snubbing diode.

You have not described the switch, but no motor is going to fail during a 1mS period even if it is locked against turning. When it is locked any motor will stand a couple of seconds before the magic smoke comes out of it. Are you absolutely sure the motor is short circuit.The mechanism is normally surrounded by many micro switches for direction reversing and end stops. Have you checked that these are all working? and still in the right position. These little motors take a high current during their click clack rotation, 4 A is typical, can your supply still supply this?.
The clearances around the waveguide switch its self (cylinder with square holes cut through it) are very small, you have not got a load of dirt or fluff in the wave guide, causing the cylinder not to home, so the motor is being run at the 4A until it burns out?. Take apart a motor if its being overloaded, the presence of smoke damage will be obvious. If no smoke damage , then its a faulty unit as supplied.
Frank