BP star / delta

Dave K2 · Sep 9, 2009

Hi all

i'm looking at converting my bp to VFD drive but when i looked in the motor terminal box to change from star-415v to delta-220v i see the wires are numbered and not the strip joiner system i am accustomed to, can someone show me the correct number wires for low voltage/delta wiring. Its a standard US Motors brand motor on a BR2J machine.

Thanks

Dave

atomarc · Sep 9, 2009

Dave,

This site has the most common connections. Pick your motor and see what it says.

Stuart

http://www.firstelectricmotor.com/motor_connections.htm

Dave K2 · Sep 9, 2009

Thanks for that, i see its a 9 lead motor but how to tell if its a delta or wye??

I thought that was a connection method not a type of winding, what would a BP have?? :confused:

rons · Sep 9, 2009

Dave
Can you not wire from 415v Y to 220 Y?

Dave K2 · Sep 9, 2009

rons said:
Dave
Can you not wire from 415v Y to 220 Y?

Ok, now youre confusing me. Over here Delta is 220v and star is 415v.

rons · Sep 9, 2009

Dave K2 said:
Ok, now youre confusing me. Over here Delta is 220v and star is 415v.

Ok, I noticed your location. I was not aware that Delta or a Wye connection
depends on the voltage.

Several motors I own have 9 leads in Wye(Y) configuration. It means that three
of the windings are internally connected, thus 12 -3 = 9 leads. If you have 9 wires
you cannot make a Y motor a Delta motor because of the internal connection. You can
only make changes for high or low voltage in the Wye(Y) configuration.
If you want I can post up a picture of what I'm talking about.

How many wires exit from the motor housing? Take a good look at the motor nameplate
and tell me what you see.

Dave K2 · Sep 10, 2009

rons said:
Ok, I noticed your location. I was not aware that Delta or a Wye connection
depends on the voltage.

Several motors I own have 9 leads in Wye(Y) configuration. It means that three
of the windings are internally connected, thus 12 -3 = 9 leads. If you have 9 wires
you cannot make a Y motor a Delta motor because of the internal connection. You can
only make changes for high or low voltage in the Wye(Y) configuration.
If you want I can post up a picture of what I'm talking about.

How many wires exit from the motor housing? Take a good look at the motor nameplate
and tell me what you see.

Hi

It looks like a "dual voltage delta connected 9 lead" motor according to the nema site listed above.

Its currently connected for 415v as follows...
supply to 1 - 2 - 3
6&9 joined
8&5 joined
4&7 joined

The plate states 1-1/2hp, 210v @ 5A / 420v @ 2.5A, 50hx, 1440 rpm.

rons · Sep 10, 2009

Dave K2 said:
Its currently connected for 415v as follows...
supply to 1 - 2 - 3
6&9 joined
8&5 joined
4&7 joined

Hi,

The configuration is standard. I have five three phase motors which are exactly
like this. The "joined" connections connect in series two windings for each phase,
thus double the voltage potential. To convert to low voltage connect as follows:

6,5,4 joined (completes a Wye connection center point)
3&9 joined
1&7 joined
2&8 joined
supply to 1 - 2 - 3

It is impossible to configure the 7,9,8 windings as a Delta because they are
internally connected as a Wye.

It is possible to configure then 3,6 & 1,4 & 2,5 windings as a Delta but don't
do it unless you want to experiment and possibly damage the motor. The
motor was designed in low voltage format to distribute the current to all
six windings. Running only three in Delta mode, I'm not sure if anybody has
ever attempted that. Short answer, follow the Wye connection above and
forget about the Delta idea.

Dave K2 · Sep 10, 2009

rons said:
Hi,

The configuration is standard. I have five three phase motors which are exactly
like this. The "joined" connections connect in series two windings for each phase,
thus double the voltage potential. To convert to low voltage connect as follows:

6,5,4 joined (completes a Wye connection center point)
3&9 joined
1&7 joined
2&8 joined
supply to 1 - 2 - 3

It is impossible to configure the 7,9,8 windings as a Delta because they are
internally connected as a Wye.

It is possible to configure then 3,6 & 1,4 & 2,5 windings as a Delta but don't
do it unless you want to experiment and possibly damage the motor. The
motor was designed in low voltage format to distribute the current to all
six windings. Running only three in Delta mode, I'm not sure if anybody has
ever attempted that. Short answer, follow the Wye connection above and
forget about the Delta idea.

Many thanks, i'll use your low voltage plan.

Dave

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