Star delta starter: resistor calculation

Hello Guest Daniel,

<"I want to know how I can calculate the value in ohms and watt of the resistor of a Wy starter in 3x220VCA and in 3x460VCA?">

So do I.

What is a Wy starter?

What is 3x220VCA?

What is 3x460VCA?

These are all unknown.

Also you need to know the motor specifications, which you have failed to supply.

The questions you are asking, look like a "Homework Question" and we don't do those, refer: CR4 Frequently asked questions.

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If your question is not for homework, reply here please, with

Kind Regards....

Standard star delta starters do not have resistors.

If you are talking about a closed transition star delta starter (see http://www.lmphotonics.com/star_delta.htm) then you need to provide more information, however the basic idea is that when you open the star contactor, current will continue to flow through the windings via the resistors. The magnitude of this current should be in the same order of magnitude as the current in star.

The resistors can be calculated from this known current and the voltage across them. Note: the power factor at start will be in the order of 0.2 so that needs to be taken into account. The voltage across the resistors will be approaching lin voltage.

Best regards,
Mark Empson

http://www.LMPhotonics.com | http://www.LMPForum.com