DC activated AC relay

[mainline]

You don't need a DC relay, for instance a 24v 2 pole contactor would be better using a simple 24v transformer.

 

[dave-novice]

I looked closer at the old 3phase relay and you are dead right the coil side is 24vac so I'd be able to re-use the relay.
Been looking at the transformers from 240vac to 24vac there was a earlier post saying about only needing milliamps that's the next question in 24vac what amp transformer should I look at for the 3phase relay?
Cheers Dave

 

[dave-novice]

Hello again everyone, sorry to keep posting/annoying for answers.
The old 3phase contactor/relay is a c-12d10 with 24vac coil could anyone tell me the amps/Millie amps needed to operate the relay?
Cheers Dave

 

[dave-novice]

You don't need a DC relay, for instance a 24v 2 pole contactor would be better using a simple 24v transformer.

Hello mainline, I looked at the contactor/relay that was for the 3phase it has a 24vac coil.
Model c-12D10 I'm thinking of using this but only utilising 2 contactors but what amp transformer would this work with?
Being AC 50-60hz I'm hoping it wouldn't need 1amp or over but I don't know I can't use existing transformer from the old setup as it rated input is 415v.
If you had any idea that would be greatly appreciated.
Cheers Dave

 

[James]

Get the same Va rating as the original.

 

[w0z]

Contactor data sheet
Some coil specifications page 6 to give you some idea of operating and holding currents.
I'm not sure what the issue is with coil current, it's relatively low (note specs are in VA not amps)

 

[mainline]

Hello mainline, I looked at the contactor/relay that was for the 3phase it has a 24vac coil.
Model c-12D10 I'm thinking of using this but only utilising 2 contactors but what amp transformer would this work with?
Being AC 50-60hz I'm hoping it wouldn't need 1amp or over but I don't know I can't use existing transformer from the old setup as it rated input is 415v.
If you had any idea that would be greatly appreciated.
Cheers Dave

Haydon 24V AC/AC Power Supply Transformer

A range of Haydon 24 volt AC power supplies transformers with a total cable length of 3.8 metres available with 1, 2 or 4 Amp ratings. (MPN: HAY-24VPSUINLINE2A) (Model: HAY-24VPSUINLINE2A)

connectec.uk

 

[Avo Mk8]

Model c-12D10 I'm thinking of using this but only utilising 2 contactors but what amp transformer would this work with?

If the contactor was made by Allen Bradley the C-12D10 info appears to say it's a 120v coil !

100-C12*10

Allen-Bradley MSC-C - contactors. The Allen-Bradley 100-C12*10 is a 3-phase IEC rated contactor used for the control of electric motors. It is rated 2 HP at 230V and 7.5 HP at 460V. Conforms to IEC/EN 60947-4-1 / 5-1 AB C12 10 AC Operating Coil Voltage: Options listed belowother 100-c contactors...

controlparts.com

Its rated correctly for the 3-phase motor, but not for your single phase replacement.
I think the coil current will be well under 1A, but I haven't seen its current consumption mentioned in the data sheets.

Does the existing low voltage transformer not have a primary tap for 220/240V as well as the 415V connection?

 

[w0z]

If the contactor was made by Allen Bradley the C-12D10 info appears to say it's a 120v coil !

100-C12*10

Allen-Bradley MSC-C - contactors. The Allen-Bradley 100-C12*10 is a 3-phase IEC rated contactor used for the control of electric motors. It is rated 2 HP at 230V and 7.5 HP at 460V. Conforms to IEC/EN 60947-4-1 / 5-1 AB C12 10 AC Operating Coil Voltage: Options listed belowother 100-c contactors...

controlparts.com

Its rated correctly for the 3-phase motor, but not for your single phase replacement.
I think the coil current will be well under 1A, but I haven't seen its current consumption mentioned in the data sheets.

Does the existing low voltage transformer not have a primary tap for 220/240V as well as the 415V connection?

The contactors can be ordered with 24V AC coil but the code might have a K J?
Notwithstanding that if no 240V tap I'd connect 240V mains to the transformer 415V primary (fingers out!) and measure the transformer output volts. You may not need another transformer.

 

[dave-novice]

Just an update I do have the 24vac model of that relay.
I tried w0z's advice and yes the 415v original transformer is activating the relay on 240v main power so I am smiling happy days.
I'd just like to add a big thankyou to everyone who gave me feedback and advice, couldn't have done it without you.
I'll post a before and after pic of the project when near completion.
Cheers dave