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#69138 - 08/29/06 04:01 PM Lathe motor
derater Offline
Registered: 03/30/02
Posts: 179
Hope this is an ok area for the ?. Cust. has a Powermatic 3520b lathe and all I can find is that it's 3 or single phase, 2hp. Someone (co. ?) told him it takes a 40a breaker. Does this seem excessive? Resi basement location.
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#69139 - 08/29/06 04:38 PM Re: Lathe motor
Bob Offline
Registered: 02/05/02
Posts: 182
Loc: Mobile, AL, USA
Look on the motor nameplate and get the FLA
(full load amps). If its single phase the FLA should be about 12 amps. Use a 25 or 30 amp breaker. If its 3 phase the FLA should
be about 7 amps. 15 or 20 amps breaker. usually a residence does not have 3 phase service. You may have to change the motor.
#69140 - 08/29/06 04:57 PM Re: Lathe motor
electure Offline

Registered: 12/24/00
Posts: 4259
Loc: Fullerton, CA USA
Don't be too quick to jump to the conclusion that it's a 230 volt wired motor.
A 2hp motor will draw about 24 amps when wired for 115.
If that were the case, a 40A Breaker wouldn't be excessive
#69141 - 08/29/06 05:11 PM Re: Lathe motor
LarryC Offline
Registered: 07/05/04
Posts: 780
Loc: Winchester, NH, US
If it a 3 phase motor, you can use a small VFD to generate the 3 phase from a single phase input.

#69142 - 08/29/06 05:47 PM Re: Lathe motor
derater Offline
Registered: 03/30/02
Posts: 179
Thanks guys. It's an either/or unit. I don't carry 8-2 in the van and was hoping against another trip for wire. Electure, is that run or start? Does that apply?
#69143 - 08/30/06 08:09 PM Re: Lathe motor
RobbieD Offline
Registered: 02/23/03
Posts: 231
Loc: Canada
Here is the link with the manual for the lathe. It seems wierd that in the specs it doesn't list the FLC. It does state that it is a 230v motor like you said single/or three phase.
#69144 - 08/30/06 09:13 PM Re: Lathe motor
NORCAL Offline
Registered: 09/25/02
Posts: 865
Go to page 13 of the manual, it already has a inverter.
#69145 - 08/30/06 09:32 PM Re: Lathe motor
Scott35 Offline

Broom Pusher and
Registered: 10/19/00
Posts: 2707
Loc: Anaheim, CA. USA
Viewed the .PDF manual, available from the link that RobbieD provided.

Found out the following about this Lathe:


[*] The Lathe Motor is powered and controlled via an intregal VFD, which is Factory installed,

[*] The Motor is a TEFC make, rated for 2 HP at 220V, 60 Hz,

[*] No indication if the 2 HP Motor is Single Phase or Polyphase - but seeing that the Motor is controlled by a VFD, I am thinking it would be a Polyphase Motor - likely a Wye connected TEFC type 3 Phase Squirrel Cage Induction Motor,

[*] The machine may be connected to either a 1 Phase 230 Volt power system, or a 3 Phase 230 Volt system,

[*] If 1 Phase 230 Volt, 2 Wire system is used, the Factory's Standard 3 wire cord, supplied with the machine, may be used and no alterations need to be made to the machine,

[*] If 3 Phase 230 Volt 3 Wire system is used, the cord needs to be changed out with a 12/4 cord, and termination alterations are required.

No FLA ratings are listed anywhere, so it seems like the Branch Circuit might be best rated for the FLA of a 2 HP 230 Volt 1 Phase Squirrel Cage Induction Motor.

As viewed by the NEC, this would result in at least 12 FLA for a 230 Volt Motor, and at least 13.2 FLA for a 208 Volt Motor.

Looks like a 20 Amp Circuit would be sufficient for the Lathe, and a Breaker from 20 Amps to 40 Amps could be used.

Definitely need to do these two things first:

1: Check the nameplate's ratings, and base circuitry ratings from that,
2: RTFM!!!
(stands for: Read The Fu..,, err... Fine Manual)

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
#69146 - 09/01/06 04:32 AM Re: Lathe motor
derater Offline
Registered: 03/30/02
Posts: 179
Thanks all- I finally got to see the lathe; nameplate read 17.5a @ 240v 1ph.Used 10-2 for the circuit,20a bkr. Why 'they' told the h/o 40a is beyond me.

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