Control transformers in 3 phase environment

[Rmetz]

I am used to using 120/240 V input control transformers in the single phase environment. In some European environments only the three phases and ground are available, so the control transformer input has to go phase to phase. Can anyone give advice on manufacturers of control transformers (20VA region) that makes product for 400V input? The US manufacturers seem to all only make 120/240V versions.

 

[ScottyUK]

Where are you located? Flying iron across the Atlantic is normally the preserve of the military.

I could give you plenty European manufacturers but there's not much point if you're in the US or Canada.


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If we learn from our mistakes I'm getting a great education!

 

[Rmetz]

I am in the US but so far have not had any luck finding a US manufacturer with a standard product with CE. I can get what we need easily, but not with CE - that is the problem. If you have suggestions for European manufacturers, particularly ones that would have a standard product line that carries CE automatically, I would still be interested in checking them out. Some may have US distribution, e.g. we buy WIMA parts regularly.

Thanks!

 

[itsmoked]

Check:

http://www.solaheviduty.com/products/transformers/Industrial/ICE.html

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[jraef]

If you have a 400V 4 wire system the line to neutral voltage is 230V, so if you INSIST on having 120V controls (not advisable in many IEC countries by the way), then you can simply use the 230V as the input to a standard CPT and get 115V output.

Why I say that (nominal) 120V control is ill advised is that in many IEC countries they will not be used to 120V as a control voltage, their wiring standards are different, and spare or replacement parts will be difficult for them to procure in an emergency breakdown situation. they typically go with either 230V control or more recently, 24VDC. So a better choice for more universal appeal is to go with 24VDC control and a decent power supply instead of a CPT.

 

[itsmoked]

An omnivorous switcher from whatever to 24VDC can cost about the same as control transformer and weigh 1/2 so that is certainly I nice way to go if 24VDC floats your boat.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[ScottyUK]

110V AC is pretty standard for big contactors in the UK so it is common in the heavy process industries and utilities. We don't normally specify 24V DC control as a rule, but the reverse situation is common in the PLC-oriented manufacturing industries. 24V isn't much use for switching really big stuff, but it is a good choice if the loads are relatively small contactors up to (say) 25kW. Much above that the economics start to swing in favour of a transformer, and once the contactors are in the 90kW+ area 24V types just aren't readily available.

It might be worth checking out Farnell Electronics because I know they have a tie-up with Newark so we can get Newark parts in the UK: I assume a reciprocal agreement probably exists. RS Components are another big UK distributor, after that the electrical wholesalers like Newey & Eyre would be a good starting point. What sort of quantity are you looking for? If you need larger quantities I will dig up a couple of suppliers who we have used in the past.


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If we learn from our mistakes I'm getting a great education!

 

[Rmetz]

jraef: I don't think you understood the problem: We don't insist on using 120VAC for controls: What I am looking for is suppliers of control transformers with inputs that are compatible with a 400VAC line-to-line input, for operation in a 4 wire 3P + E environment, in other words neutral is not available. The output of the transformer then supplies all the low control voltages.

Thanks!

 

[itsmoked]

Look at SOLAS ICE control transformers. They are made for CE applications.

Note the 400V primaries.

http://www.solaheviduty.com/products/transformers/Industrial/CESelection.html

You can probably get these at NEWARK or Allied-Electric

BTW: You don't need a neutral. The transformer creates a new isolated source from across the two 'lines'. You then ground one side of the secondary,(low voltage in your case), making it the neutral of your control source.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com