controller problems

[hall99m]

I have been using hugh piggots triac heat control circuits to regulate power from my 1kw home built windmill.  

I use two circuits together at a time, switching two of three phases for each heating element. This only works to a fashion because one switch comes on just before the other, at times creating an imbalance in the machine.  

My idea now is to use a single triac circuit at a time to switch on a relay which would switch the load evenly.  

I have connected up a relay to switch the first load and it works well, but when I try to do the same for the next load the relay just chatters, not coming on properly at all, this also happens to the relay even when it isn't switching any load.  I have tried swapping relays around but it makes no difference.  

The windmill produces around 100vac 3 phase 50 Hz so I am using 115vac relays which run on the mills own power.

Any help would be much appreciated.

[dnix71]

The mill produces 100 vac and the relays need 115 vac according to your post.

That suggests a problem right there. If you dump into batteries, then running a small inverter from the batteries would give you a stable voltage for a relay.

[laskey]

Yah, generally 115VAC relays will come on around 90VAC, but you can't be sure of exactly when.

I've been looking at hugh's circuit.  If you hang a relay on the triac, you may not be drawing enough current to keep the triac on all the time.  They may act like a switch generally, but you need to draw a current through them or conduction colapses.  It's different for ever make of triac too.  Try adding a load resistor in parralelle, with the relay coils, just to push up the draw thru the triac a bit higher.  A resistor will also give you some "freewheeling" on the relay coil.

Regards,

Chris

[Flux]

I would be very reluctant to use ac relays on a raw windmill supply especially if the frequency is less than 50Hz. Ac relays are not the best of things and really need their rated voltage and frequency for the shading bands to work properly, unshaded ac electromagnets drop out every half cycle.

I am not sure if you have other problems with the control scheme, it may be that you have if one relay works.

I would use dc operated relays if you have to go to mechanical things but I really can't see why static relays won't work if you gate them on properly . Not really a duty suited to mechanical relays.

Flux

[hall99m]

I don't think my alternator output voltage is as high as I first thought, I've been reading the voltage on an analogue voltmeter and I now tried reading it with a digital meter and it is a bit lower.  Also I notice that when the first relay pulls in the voltage dips slightly, making the next relay not pull in properly, so I tried using a 110vac coil relay instead of the 115vac one and it seems to work fine.  I'm going to replace all the 115vac relays with 110vac ones and see how it goes.