220VAC 3phase question

[myersjx]

i have never worked with 220VAC 3 phase power before. The application requires a control relay to be used to start a VFD in the existing system. The plant responded that the control voltage was 220VAC as well. I thought this was a mistake having never worked with anything over 120VAC. My question is how do you get the 220VAC single phase from the 220VAC three phase. I have become very confused with this.

 

[ultramegabob]

I have never heard of 220 three phase

 

[jrannis]

i have never worked with 220VAC 3 phase power before. The application requires a control relay to be used to start a VFD in the existing system. The plant responded that the control voltage was 220VAC as well. I thought this was a mistake having never worked with anything over 120VAC. My question is how do you get the 220VAC single phase from the 220VAC three phase. I have become very confused with this.

Use any two of the three phases.
Check back in in the morning and let us know how it went

 

[benaround]

myersjx,

Welcome to the Forum !!

220v 3ph power is not a recognized system. It might be 240v 3ph or it may

be 120/208v 3ph 4wire, but ultramegabob may have not heard of those either

jrannis has given you the answer to your question. good luck!

 

[jim dungar]

Use any two of the three phases.
Check back in in the morning and let us know how it went

Actually you should use any two of the phase conductors. Any two conductors will give you a single voltage.

 

[ATSman]

Stinger

Stinger

3 phase 240V systems were used years ago and were a cheap way of getting
a 120V circuit by center tapping one phase winding. This leg was called the
"stinger" leg and you had to be carfull not to use this leg when connecting
to a 3 phase motor.

 

[George Stolz]

Tony, welcome to the forum.

3 phase 240V systems were used years ago and were a cheap way of getting
a 120V circuit by center tapping one phase winding. This leg was called the
"stinger" leg and you had to be carfull not to use this leg when connecting
to a 3 phase motor.

A 3 phase load can be connected to a 120/240V delta source with a high leg. The high leg is only high between it and the neutral of the source.

The voltage between every phase of a 240V delta transformer is 240V.

If you were to connect what is supposed to be a 120V load to the high leg of the system and neutral, you would subject it to around 208V instead of 120V, resulting in letting the smoke out of the load.