Using Contactors or large electrical loads.

[G-Dog]

Contactors are switches that are used to control larger loads and are generally controlled with lighter circuits. In your car, for instance, you have small wires going to your ignition switch that control a contactor for your starter. The wires that go to your starter motor are huge and if they had to be routed into the car to be operated by a switch they would be even larger. You could have wires that are 3/4" thick going to your ignition switch and that is not too practical.

In a grow operation you may have one or several lights that you would like to control with a contactor. The advantages include having one small switch (timer) control large banks of lights periodically.

Every time a timer connects a large load it arcs. Many of the timers are manufactured with just the bare minimum requirements and every time you start the lights it gets very hot for an instant. This heat breaks down the connectors each time it connects. Over time these connectors start to wear. In a two month flower period your timer will see 60 or more starts and each one is wearing the contacts away. As the contact wear they make electrical resistance and more heat which increases breakdown. A better solution would be to control a contactor (which uses very light power) with your timer.

There are various kinds of contactors out there and I will be showing those and suggested wiring methods for controlling the contactors.

 

[TorturedSoul]

Contactors are switches that are used to control larger loads and are generally controlled with lighter circuits. In your car, for instance, you have small wires going to your ignition switch that control a contactor for your starter. The wires that go to your starter motor are huge and if they had to be routed into the car to be operated by a switch they would be even larger. You could have wires that are 3/4" thick going to your ignition switch and that is not too practical.

That's just a regular relay on the starter circuit, isn't it? Don't think there's a hold provision on it.

 

[G-Dog]

That's just a regular relay on the starter circuit, isn't it? Don't think there's a hold provision on it.

I have heard the term Relay, Solenoid and Contactor used to describe that part that connects the power wires to a starter motor.

Relays are usually pretty small and solenoids usually control plumbing of fluids.

When you talk about the hold provisions there are a lot of circuits that are held in a state in your car, but the starter itself is only momentary... enough to turn over the engine and get it running.

 

[420relief]

Every time a timer connects a large load it arcs. Many of the timers are manufactured with just the bare minimum requirements and every time you start the lights it gets very hot for an instant. This heat breaks down the connectors each time it connects. Over time these connectors start to wear. In a two month flower period your timer will see 60 or more starts and each one is wearing the contacts away. As the contact wear they make electrical resistance and more heat which increases breakdown. A better solution would be to control a contactor (which uses very light power) with your timer.

I guess it would depend if your pushing the maximum rated load on your timer. Most 24 hour dial timers have a load of 40 amps. I agree the contacts in the timer are not the heaviest duty but their adequate for lighter loads.

The only light power in a contactor is the coil, that shuts the contactor when the timer turns on. The contactor is still only as good as the max rating, 30,50,or 60 amp. It does make for a nice setup, and to have just one timer to work all lights is great.

 

[G-Dog]

I guess it would depend if your pushing the maximum rated load on your timer. Most 24 hour dial timers have a load of 40 amps. I agree the contacts in the timer are not the heaviest duty but their adequate for lighter loads.

The only light power in a contactor is the coil, that shuts the contactor when the timer turns on. The contactor is still only as good as the max rating, 30,50,or 60 amp. It does make for a nice setup, and to have just one timer to work all lights is great.

I know there are quality differences in everything out there, but it seems like most of the timers I have seen are not rated for the loads you have seen.

And after reviewing my writing, I see a correction I need to make; a timer sees arcing when they turn on and when they turn off. So in a 2 month flower period you see 120 cycles.

I am an automation and controls specialist, so I tend to try to do things in that way. I just thought I would throw this thread out to offer my help if anyone wants to know more about them.

I have used contactors for many things and specifically lighting contactors in industry controlling large banks of HID lighting.

 

[diesel farmer]

I install them all the time, they work great for large lighting loads. This may be a little over the top for the joe grower, you do need some electrical experience to set up contactors in conjunction with timers and or switches.

 

[Keith Lake]

Much respect to my friends with advanced electrical knowledge

I do want to suggest to the casual reader that this seems something best left to the professional electrical engineer / electrician.

Be careful our there

 

[basementdwell]

contactors are good when cycling often. Like in your electric stove if you stand by the oven while ur waiting for ur brownies to finish, you will here ur contactors cycling as the thermostat in the oven adjusts. they use high voltage on the cowl rod heaters and use the contactor to turn them on. I would say go for it if your using 6-10 kw on one timer. or if you got 10 timers you dont want to have to sync. If not just follow the specified amp draw in the timers directions. No real gains here I have never seen a timer go up in flames but i could see some people using the 5$ low draw ones vs the 30+ amp ones i ve used for years with my Clark Griswold type Christmas setup Most of the cheaper timers are rated for 15a amps same as most house hold circuits