[Deanpeddle]

Hi ... bought a 10 HP (40 amp) single phase electric motor for my mill. I have pics but can't upload for some reason (maybe because of my account type? not sure). Anyway, there are 4 wires - 2 hot (Black, Red), 1 neutral (White) and 1 ground (bare copper). However, When I took the cover off the back of the motor I noticed that the white wire is not connected and has been taped off (quite obvious from the taping that it was done deliberately - this is not just a wire that has slipped off). Is there a particular reason for that to be done?

 

[Wiredindallas]

Are you referring to wires in a cord feeding into the motor having a white wire? If so, it was simply not needed because your motor is straight 240 volts (arrived between 2 hots).

 

[Deanpeddle]

Are you referring to wires in a cord feeding into the motor having a white wire? If so, it was simply not needed because your motor is straight 240 volts (arrived between 2 hots).

yes - there are 4 wires going into a short piece of conduit attached to the back of the motor but, on the motor, the neutral is not attached. Ok ... so that's perfectly ok then? GREAT!!! and thanks for your help.

 

[J. V.]

I hope you are not using this motor on your residential power company account/bill?
If you are, your electric bill is going to sky rocket.
Do you know how much money a 10 hp motor will cost to operate?
I don't know off hand, but there are calculators online that you can use.

 

[mpoulton]

I hope you are not using this motor on your residential power company account/bill?
If you are, your electric bill is going to sky rocket.
Do you know how much money a 10 hp motor will cost to operate?
I don't know off hand, but there are calculators online that you can use.

Similar to a small electric furnace or tankless water heater. Unless he's running it for hours every day, he's probably not going to raise his power bill much. Would cost about $2.50 per hour to run at full load, at $0.13/kWh

 

[Kevin_Essiambre]

Similar to a small electric furnace or tankless water heater. Unless he's running it for hours every day, he's probably not going to raise his power bill much. Would cost about $2.50 per hour to run at full load, at $0.13/kWh

The POCO may catch onto him starting a 10hp electric motor and charge him more...

The POCO here wants to know if you have anything larger than 5ph on a residential service...

Sent from my new phone. Autocorrect may have changed stuff.

 

[carmusic]

you need a 90-100 amp breaker for that circuit (240v), typical single phase motor stops at 7.5 hp, do you have a pic of the nameplate of the motor?

 

[Shadow99]

The POCO may catch onto him starting a 10hp electric motor and charge him more...

The POCO here wants to know if you have anything larger than 5ph on a residential service...

Sent from my new phone. Autocorrect may have changed stuff.

Actually 4hp max for Hydro One . 5hp up to 10hp requires a reduced voltage starter (or VFD).
Above 10hp, you need permission from the engineering staff.


I'd think most pocos are similar on this.

 

[Shadow99]

you need a 90-100 amp breaker for that circuit (240v), typical single phase motor stops at 7.5 hp, do you have a pic of the nameplate of the motor?

Quick calc without nameplate, I get 125A breaker !

 

[Kevin_Essiambre]

Actually 4hp max for Hydro One . 5hp up to 10hp requires a reduced voltage starter (or VFD).
Above 10hp, you need permission from the engineering staff.


I'd think most pocos are similar on this.

Ah, interesting. Thanks for this information.

I thought it would be up to and including 5 horsepower (my dad's Compressor has a 5hp motor on it...).

Sent from my new phone. Autocorrect may have changed stuff.

 

[Shadow99]

Ah, interesting. Thanks for this information.

I thought it would be up to and including 5 horsepower (my dad's Compressor has a 5hp motor on it...).

Sent from my new phone. Autocorrect may have changed stuff.

Compressors are notoriously over rated

I bet the nameplate has no more than about 17A on it :wink2:

 

[Kevin_Essiambre]

Compressors are notoriously over rated

I bet the nameplate has no more than about 17A on it :wink2:

Maybe, maybe not... we changed the motor on it when the last one let the smoke out!

I know the factory assemblies are way over rated from what they actually are.

Sent from my new phone. Autocorrect may have changed stuff.

 

[J. V.]

I remember once someone did the calculation on a 100 hp three phase motor continuous operation.
It was $100,000 per year.
I could be wrong, but I would think that motor significantly increases his power bill depending on how much he uses it and how many times he starts it.

10 HP in a residential setting is a beast.

 

[Kevin_Essiambre]

I remember once someone did the calculation on a 100 hp three phase motor continuous operation.
It was $100,000 per year.
I could be wrong, but I would think that motor significantly increases his power bill depending on how much he uses it and how many times he starts it.

10 HP in a residential setting is a beast.

That's a lot of loonies.

I'd sooner use a internal combustion engine for this than pay the bill for running an electric motor... and a diesel would have the torque needed.

Sent from my new phone. Autocorrect may have changed stuff.

 

[mpoulton]

I remember once someone did the calculation on a 100 hp three phase motor continuous operation.
It was $100,000 per year.
I could be wrong, but I would think that motor significantly increases his power bill depending on how much he uses it and how many times he starts it.

10 HP in a residential setting is a beast.

$100,000 per year for 100HP continuously is $0.11 per hour, per horsepower. If he runs his 10Hp motor at full load for 8 hours per day at those rates it'll cost him $9.13 per day, or $182.60 per month if he does it every weekday. That's a whole lot of home machine shop time, though.