I need to drive an AC solenoid that says 3VA in the case and measures 5ohm with a multimeter.
AC voltage is 110V and I want to use a triac, maybe a MAC15D. Is this enough? Should I put a snubber circuit in parallel to the triac?
The solonoid impedance is 4K, so the current is low but a snubber is always a good idea. If you can switch at a zero crossing, you won't need a snubber.
How about both?, if you have zero voltage you have zero current, and likewise, if you have voltage you automatically have current - assuming a conducting path is present.
How about both?, if you have zero voltage you have zero current, and likewise, if you have voltage you automatically have current - assuming a conducting path is present.
Nigel, I think you are forgetting about reactive loads - in this case, inductive.
I don't claim to know much about triacs, but here is an informative app note on driving inductive loads with a triac.
I think our OP is going to need a small triac for this application. With a solenoid impedance of 4k, the peak current will be on the order of 40mA. The holding current of the MAC15D is 40mA max, 20mA typical. **broken link removed** has triacs with hold currents as low as 5mA.
Thank you all for your answers! but I still have some doubts. How do you calculate 4K impedance? The solenoid I want to drive is about 3"X3"X3" so it doesn't look that little and it is pretty powerful, 40ma seems very little current for this kind of solenoid.
Thank you all for your answers! but I still have some doubts. How do you calculate 4K impedance? The solenoid I want to drive is about 3"X3"X3" so it doesn't look that little and it is pretty powerful, 40ma seems very little current for this kind of solenoid.
You said it had 3VA printed on the case.
3VA/120V=25mA
120V/25mA=4.8kohms impedance. That would be a 12.7 Henry inductor. Sounds very high for only 5 ohms resistance.
Maybe 3VA doesn't mean 3 volt-amps.
Do you have an AC ammeter?
How about both?, if you have zero voltage you have zero current, and likewise, if you have voltage you automatically have current - assuming a conducting path is present.
How abt either-or.
That is the priciple behind resonant converters (never got one to really work mind) you either have ZVS (zero voltage switching) or ZCS (zero current switching) the principle being to remove the switching loss from a converter
The case rating of 3 VA was completey wrong, I measure the current with an ammeter and it measures 12A and 25A if the plunger was out of the solenoid.
I think I will need to use a 30A triac at least.