Sizing a control power transformer 1

[bdn2004]

We bought piece of equipment that has a 630VA control power transformer. When I add up the connected load I come up with over 800 VA connected to it. It feeds (2) small plcs and a little servo motor. I'm wanting to add a 30VA circuit to this. We are getting little help from the OEM on anything and they are in a foreign country. I'd ask them...but.

I notice this transformer has VDE rating of 800VA and another marking saying 2000VA. I don't know what this means. Attached is a picture.

It's protected by 2A fuses on the primary side.

My question is...would you change out this transformer to say a 1000VA or justify the extra loading by saying most likely the load is diversified. This is a brand new piece of equipment that has never been hooked up.

 

[Skogsgurra]

The 800 VA rating is the German rating and the 2000 VA Kurzzeitlast is what it can take when a contactor coil is switched in (short term load, transient load).

I think that the transformer is OK but that you should consider adding a separate transformer for your additional load. It costs less to do so and you will avoid possible guarantee problems that could be an issue if you change the existing transformer.

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[itsmoked]

Totally agree with Skogs assessment.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[bdn2004]

I like this idea, but I don't specify this stuff everyday. Any help on a good, reliable control power transformer? I looked at a Square D 9070TF series that has the primary fuses on top and I am assuming they come with a cover for these. Grainger cat. no. 4R924.

This seems the simplest and the cheapest solution. I don't see ever having to change the primary fuses and what this feeds has a 120V circuit breaker.