A little help please...

[SpyroS]

Hi guys

Got a problem at work, I work for a plastics company. Our moulds have 240v heaters in them, they are expensive and are blowing all the time. I think its the controllers, maybe causing a spike. I don't have a o-scope, so i can't check.

I was thinking of putting a surge protector cap across each heater. would it work?
Any help or suggeestions please.

Cheers

[Banthai]

Hi Spiros

I work on high speed packaging lines and some of these use 240v heaters on the sealing jaws

ok not exactly the same ... but we do experience the blowing of heaters occasionaly ...

our heaters consist of a metal cartridge tube with a resistive element embeded in a ceramic core for insulation

these heaters dont really tend to blow because of spikes as they are just a resistive element ( a giant resistor of a few ohms )

the ones that i have encountered that have blown ... have usually blown because of shock or continious impact from a mechanical action .... over time this tends to breakdown the ceramic core to a powder .... which allows the element to touch the outer metal tube.... which shorts the 240v and blows the element .....

the only issues we have had with spikes on the supply causing problems ... is when they cause the Electroninc PID temperature controllers to malfunction causing the elements to overheat

so if this is the case it would be better fitting a mains filter prior to the controller


all the best ...

Karl

[SpyroS]

Thanks Karl

I think we are using the same heater cartriges. the shorter ones never seem to blow, but the 85mm and 110mm blow dayly. The mechanical impact may be the cause, but it only seems to happen on certain moulds. We've change numerous controllers and nothing seems to work. We us Technotemp digital controllers.

I just picked up some MOV protectors, il try placing them on and see what happens. Do they go in series or parrallel?