need help with quick and dirty triac triggering please.

Hi, wondering if some kind sole can help me out.

problem is timer module on washing machine is none working with regard to
motor drive, I think the tda1085c chip is dead, machine is about 5 years old
and new timer is apparently about a 100GBP so ordered new machine, trouble
is one we want will take 10 days min so I figure I ought to be able to
manually control motor speed and get some use in the mean time.

It's quite some time since I did any meddling with electronics, I still have
quite a lot of caps and resistors though I seem to have forgotten most of
how to use them!

Anyway what I'm attempting is to put an RxC network into the old triac gate
feed instead of from the triac controller chip. I've managed to find a 0.1uf
capacitor of a type I beleive to be suitable for 250 vac,( I'm in uk so 250
vac mains), also I think I can get a 120vac feed from the large dropper
resistor that's on the board, I've got a 50k duel pot and lots of other
fixed resistors of 0.25 maybe some 0.5 watt.

The triac is marked btb15-600bce, I assume that means it's a 15 amp 600volt
but I havn't been able to get a datasheet and don't know what the trigger
values are, I also don't have any diacs so would like to drive it direct
from my RxC network, it's only a temporary measure for a few uses.

If someone can tell me whether it's feasable without the diac and perhaps
the resistance values to use with the 0.1uf cap, I'll be isolating the pot
body inside the machine out of the way with just the plastic shaft
pertruding. I also expect to have to adjust the wash speed for each
different load but it will be easier than trips to the launderette and
cheaper, so if anyone can help it would be great.

thanks in advance
kevin.

 

Subject: need help with quick and dirty triac triggering please.

Hi, Kevin. It's a little more complicated than you envision. It isn't worth
the hassle, especially if you're not sure what you're doing. And you are
talking about potentially lethal voltage in the presence of a tub of sudsy
water and a big grounded chassis.

Try the laundromat. You may spend a few more pounds, but you don't want the
excitement you may be missing as a result.

Sorry
Chris