Magnetic Starter Coil Voltage?

Hi - Recently I moved my woodshop from a 3 phase, 480v location to a single phase, 240/120 location. I wired in a phase converter to power up my 3 phase tools, and swapped the jumpers to make the tools run on the lower voltage. Now I need to replace the magnetic starters...

Do I need a starter with a 120v coil, since each leg measures 120v to ground? Or do I need a starter with 240v, because that's what it measures leg to leg?

Ugh...

Also, I ordered these: Magnetic Motor Starter Control 7 1/2hp 1hp 3ph 28v 24-36A Overload New: Amazon.com: Industrial & Scientific
But I'm thinking those are incorrect... Any help would be greatly appreciated! Thanks,

Dameronw

dameronw,

Welcome to the forum.

I would say that unless you have pulled a neutral into your electrical enclosure then you actually have no ability to access 120 volts. With the 3 phase provided by your phase converter..rotary I hope, you'll have the 240 needed for your new coil. Be sure your 240 volt control is on the 'line legs' and doesn't involve the manufactured leg produced by your converter.

While your linked mag notes a 208 coil, it should actually be OK on 230 volts.

Stuart

Product features

Telemecanique, Siemens, Furnas, Allen Bradley, Square D, GE
Motor Starter, Motor Control, Manuel Starter
7 1/2, 10 Horse Power
3 Phase, 208 Volt Coil
24,25,26,27,28,29,30,31,32,33,34,35,36 amp overload

Click to expand...

Really? It's ALL of those brands in one?

Run away... this is some piece of Chinese junk being pawned off cheap by basically preying on people who are unsure of what they want, tossing out names they know. They even can't decide if it's a magnetic starter (i.e. it has a coil voltage) or a "manuel" starter, which would not have a coil at all!

Manuel starter? Does that mean it comes with a Mexican who will push the button for you?

But it says it has a 208V coil, you do NOT want that anyway. Just get a motor starter with a 120V coil, easy peasy. Stay clear of Amazon Chinese junk and prices too good to be true. Amazon has no clue themselves, and they don't care. If the price is too good to be true, there is a reason.

Wht not just get a 120 or a 240 volt coil for and new heaters or overloads if needed? Some of that stuff is very reasonable on ebay IF you get lucky and what you need is listed. I am doing the same thing as you, a machine I got was ran on 480 and now I am running on 240V RPC. I was going yo use a line voltage coil because that is how the 480 was hooked up. But if using a 120V coil is better then I should probably go that route. I am not sure I understand why the 120V is better though, comming from Jraef gives me confidence that is the way to go.

Before you take advice on coil voltage, etc, DO THESE MACHINES HAVE CONTROL TRANSFORMERS? It's fairly common to have one, but simpler setups often use line voltage and do not employ a transformer.

You ordered parts, so maybe you do know, but we do not.

If the unit had a control transformer, then the voltage is going to be fine, no change, as long as the transformer has taps for 240V. You would still need overloads that are suitable for the current drawn at 240V, which, as you are aware, is different from (double) that drawn at 480..

If the stuff is known brands, you can probably get the coils and heaters to convert it. But heaters etc are old-school, and are not as easily available as they were years ago. Even 15 years ago I could not find heaters for a control I had, that was a known brand. I would have needed to go to a place that supports the old stuff. They exist, but I went another way with the thing, and replaced it.

Yeah, all (but one, maybe?) of the relays/contactors in my big mill have 12V coils, because all the control wiring is low voltage. Supply voltage is dropped through a control transformer, which serves to isolate the buttons and lights from the supply.

JST said:

Before you take advice on coil voltage, etc, DO THESE MACHINES HAVE CONTROL TRANSFORMERS? It's fairly common to have one, but simpler setups often use line voltage and do not employ a transformer.

Click to expand...

My machine (ironworker) does have a transformer, I think it is just to provide power to hydraulic solenoid valve. I will look and see what its output is and probably get a coil to match that.

What machines and what type of starters? My old iron machines are primarily C-H and AB 509 or 709. Both are pretty easy to source coils or the whole starter cheap. Heaters are available too. Newer machines usually do have transformers as 240v control circuits aren't used much anymore. 110 or 24 are the usual choices and transformers have taps for different voltages used throughout the world. I run most machines that have simple electronics on NOS older mag starters with 240 v coils but I'm usually trying to match the originals or at least the time period. I would stay with NEMA starters. They last forever. Euro modules are also avialable pretty reasonably on ebay as well. Increasingly they are made at least partially in China so I've replaced more of them than the old stuff but they are still a good choice. Dave