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Wire Sizes for 2 Hp 3 Phase Motor with VFD

daruta

Plastic
Joined
Apr 10, 2022
I have a 2 Hp 3 Phase 220 V motor that came with a vintage Boice Crane wood planer that I am restoring. I bought a VFD to convert single phase power for the 3 phase motor. I do not know what size wiring to use for the power supply from the 200 amp service panel to a wall receptacle, and what size wiring is needed for the power cord and plug for the machine. I found the attached wiring diagram for a pump that runs on a 2 Hp 3 phase 220 V motor where the wiring in the shop is 12 gauge from a dual pole 20 amp circuit breaker in the service panel to a 6-20 receptacle; the wiring for the machine is 12 gauge from a 6-20 plug to the VFD; and the wiring from the VFD is also 12 gauge from the VFD to the motor.

I think my set up will be similar to the pump but I have a few questions. Can 220 V go through a dual pole 20 amp circuit breaker? Can 220 V go through two (Lines 1 and 2) 12 AWG conductors for the power supply in the wall, and for the cord to the VFD? What gauge wiring is needed from the VFD to the motor? For programming the VFD, how do I know what voltage is needed for the motor? The nameplate on the attached photo does not list a voltage. I understand the VFD reduces the voltage to the motor, but I do now know what voltage the motor needs. Thank you for any input. -Dan

Sterling Nameplate.JPG
 

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Last edited:

Superbowl

Cast Iron
Joined
Feb 12, 2020
I have a 2 Hp 3 Phase 220 V motor that came with a vintage Boice Crane wood planer that I am restoring. I bought a VFD to convert single phase power for the 3 phase motor. I do not know what size wiring to use for the power supply from the 200 amp service panel to a wall receptacle, and what size wiring is needed for the power cord and plug for the machine. I found the attached wiring diagram for a pump that runs on a 2 Hp 3 phase 220 V motor where the wiring in the shop is 12 gauge from a dual pole 20 amp circuit breaker in the service panel to a 6-20 receptacle; the wiring for the machine is 12 gauge from a 6-20 plug to the VFD; and the wiring from the VFD is also 12 gauge from the VFD to the motor.

I think my set up will be similar to the pump but I have a few questions. Can 220 V go through a dual pole 20 amp circuit breaker? Can 220 V go through two (Lines 1 and 2) 12 AWG conductors for the power supply in the wall, and for the cord to the VFD? What gauge wiring is needed from the VFD to the motor? For programming the VFD, how do I know what voltage is needed for the motor? The nameplate on the attached photo does not list a voltage. I understand the VFD reduces the voltage to the motor, but I do now know what voltage the motor needs. Thank you for any input. -Dan

View attachment 382624
Use 12 AWG wires for everything. The 20 amp breaker will be fine but you likely could go down to a 15 amp breaker if you wish. The VFD will not change the 220 voltage from the panel. It will just change the single phase to three phase and can vary the 60 cycles per second from the power company up or down so you can control the speed of the motor. Just make sure the wires under the motor cover are set up for 220v not 440 v.
 

daruta

Plastic
Joined
Apr 10, 2022
Use 12 AWG wires for everything. The 20 amp breaker will be fine but you likely could go down to a 15 amp breaker if you wish. The VFD will not change the 220 voltage from the panel. It will just change the single phase to three phase and can vary the 60 cycles per second from the power company up or down so you can control the speed of the motor. Just make sure the wires under the motor cover are set up for 220v not 440 v.
Superbowl: Thanks for your reply above. I will install a 20 amp breaker and 12 AWG wiring for everything as you suggest. I have already confirmed the wiring inside the motor is set up for 220v, not 440. Thanks. -Dan
 

Almost Retired

Aluminum
Joined
Mar 23, 2019
Location
north central louisiana
I have a 2 Hp 3 Phase 220 V motor that came with a vintage Boice Crane wood planer that I am restoring. I bought a VFD to convert single phase power for the 3 phase motor. I do not know what size wiring to use for the power supply from the 200 amp service panel to a wall receptacle, and what size wiring is needed for the power cord and plug for the machine. I found the attached wiring diagram for a pump that runs on a 2 Hp 3 phase 220 V motor where the wiring in the shop is 12 gauge from a dual pole 20 amp circuit breaker in the service panel to a 6-20 receptacle; the wiring for the machine is 12 gauge from a 6-20 plug to the VFD; and the wiring from the VFD is also 12 gauge from the VFD to the motor.

I think my set up will be similar to the pump but I have a few questions. Can 220 V go through a dual pole 20 amp circuit breaker? Can 220 V go through two (Lines 1 and 2) 12 AWG conductors for the power supply in the wall, and for the cord to the VFD? What gauge wiring is needed from the VFD to the motor? For programming the VFD, how do I know what voltage is needed for the motor? The nameplate on the attached photo does not list a voltage. I understand the VFD reduces the voltage to the motor, but I do now know what voltage the motor needs. Thank you for any input. -Dan

View attachment 382624

unless you absolutely have to have it ....
i would avoid using a receptacle
the normal thinking in wiring anything is to avoid all possible splices and connections
between the supply and load
every break in the wire is a future problem point
 

rons

Diamond
Joined
Mar 5, 2009
Location
California, USA
Go with Hubbell twist lock plugs and receptacles if you need to plug and play.
I had drops from the ceiling using flexible conduit.
Changed to plug and receptacle.
Both worked. But sometimes the spring pressure on the lid of my Woods connector disconnects one wire and I have to re-seat the plug.
Haven't decided if the spring has to cut or something that.

 
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JST

Diamond
Joined
Jun 16, 2001
Location
St Louis
Connections do cause most of the trouble with circuits.

However, receptacles and "plug caps" are pretty reliable. As mentioned, they form a positive disconnect. And, they have the added benefit of stopping the jurisdiction of the NEC at the plug, if that is of any advantage.....

It can be an advantage, because if the plugs are disconnected, an electrical inspector cannot quarrel about anything that "might be" plugged into the receptacles.
 

daruta

Plastic
Joined
Apr 10, 2022
unless you absolutely have to have it ....
i would avoid using a receptacle
the normal thinking in wiring anything is to avoid all possible splices and connections
between the supply and load
every break in the wire is a future problem point
Thank you for your input, I appreciate it.
 

daruta

Plastic
Joined
Apr 10, 2022
Nameplate clearly says 220/440 volt. You want to configure the wiring for 220 which is what the VFD will supply.
I now realize the motor is 220 v which is how it is wired. I asked the wrong question in the initial post. Thanks.
 








 
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