Wiring a 2hp 3ph motor

[FTG-05]

I just bought a 2x72 grinder sans motor and VFD controller. I'm in the process of ordering the motor and I'll need to wire it in the my shop.

I'll be running 230 VAC 1ph to the VFD; then the VFD will run the motor.

According to this wire sizing calculator, it says I need 12 ga: http://wiresizecalculator.net/calculators/motorwiresizecalculator.htm

This is the equivalent nameplate for the motor I'll be getting:


And this is the VFD I'll be using: https://www.amazon.com/gp/product/B018GO62GC/?tag=atomicindus08-20

Distance from CB box to outlet is less than 100 feet (~75').

Recommendations for outlet and plug as well, please. I *assume* that I'll only need 230 VAC at the outlet since there is no need for 120 VAC; hence I'll be able to use 12/2 w/gnd NM-B wire.

Thanks,

 

[Bert_]

6.8A x 125% =8.5a is what we size the wire to per code.

To convert to single phase 8.5 x 1.73 = 14.7. so you need a wire good for 14.7A

 

[nadogail]

Based on Bert's figures, I would be comfortable with 14 Gauge wire; but in an abundance of caution I would prefer 12 Gauge.

 

[sberry]

12 isn't unusual or expensive, not much to save using a smaller wire. We assume you want to vary the grinder? If it was 1 speed would get a single motor. If it would work would be single phase cord and plug to a 20

 

[Norcal]

Based on Bert's figures, I would be comfortable with 14 Gauge wire; but in an abundance of caution I would prefer 12 Gauge.

14 is fine, going bigger is not going to be safer and if it results in shoving 10 pounds of **** in a 5 pound bag it will be less safe.

 

[sberry]

Yes, told the neighbor to get a 10 whip, he gets 8,, ha

 

[FTG-05]

14 is fine, going bigger is not going to be safer and if it results in shoving 10 pounds of **** in a 5 pound bag it will be less safe.

I don't have any 14 ga but plenty of 12 ga left over from adding a couple 20 amp curcuits to my shop. Any problem using 12 NM-b, 12/2 with ground?

I *assume* an L6-20 plug and recept would work.

Thanks,

 

[FTG-05]

6.8A x 125% =8.5a is what we size the wire to per code.

To convert to single phase 8.5 x 1.73 = 14.7. so you need a wire good for 14.7A

Where did the 6.8 amps come from? The motor label shows 6.2-6.0 amps.

 

[cvairwerks]

Where did the 6.8 amps come from? The motor label shows 6.2-6.0 amps.

Drive specification.....

 

[Bert_]

I don't have any 14 ga but plenty of 12 ga left over from adding a couple 20 amp curcuits to my shop. Any problem using 12 NM-b, 12/2 with ground?

I *assume* an L6-20 plug and recept would work.

Thanks,

We size the wire with the NEC table. It says 6.8A for a 2hp 240v 3 phase motor.

 

[sberry]

The left over wire is fine.

 

[FTG-05]

Drive specification.....

I have no clue what this means. You drove somewhere and got a specification? You found a drive on your computer and it had a specification? if so, which spec?

We size the wire with the NEC table. It says 6.8A for a 2hp 240v 3 phase motor.

That's what I looked for earlier, with no luck.

Which NEC Table?

Thanks!

 

[FTG-05]

12 isn't unusual or expensive, not much to save using a smaller wire. We assume you want to vary the grinder? If it was 1 speed would get a single motor. If it would work would be single phase cord and plug to a 20

1-2 hp 3ph motors along with a VFD are very popular with knifemakers and their 2x72 belt grinders. Got the grinder, now I want to incorporate the motor along with VFD. Since I'm going the 3ph/VFD route plus have plenty of room for another 230 VAC circuit, I decided to go with the 2 hp.

3ph plus VFD allows you to vary the speed by quite a bit, very helpful when using differenty type belts on different type materials. Especially when you're trying to prevent an "Oh ****!" error on an almost finished knife.

Thanks,

 

[wyliesdiesels]

Where did the 6.8 amps come from? The motor label shows 6.2-6.0 amps.

see table reference at end of quotes.

Motor circuits are to be wired based on table FLC not motor nameplate amps

Drive specification.....

aww no

We size the wire with the NEC table. It says 6.8A for a 2hp 240v 3 phase motor.

I have no clue what this means. You drove somewhere and got a specification? You found a drive on your computer and it had a specification? if so, which spec?

That's what I looked for earlier, with no luck.

Which NEC Table?

Thanks!

you looked in nec article 430?

stroll on down to T430.250 and you will see what Bart is referring to

http://electrical-planning.blogspot.com/2014/04/corrientes-plena-carga-de-motores-motor.html

 

[cvairwerks]

I have no clue what this means. You drove somewhere and got a specification? You found a drive on your computer and it had a specification? if so, which spec?

Thanks!

The specifications on the VFD state that it requires 6.8 amps input to provide the necessary output....

 

[FTG-05]

see table reference at end of quotes.

Motor circuits are to be wired based on table FLC not motor nameplate amps

aww no

you looked in nec article 430?

stroll on down to T430.250 and you will see what Bart is referring to

http://electrical-planning.blogspot.com/2014/04/corrientes-plena-carga-de-motores-motor.html

I looked at a bunch of them, but don't recall that one. I see the 6.8 now.

How does that impact the wire size?

 

[Dumber than lumber]

1-2 hp 3ph motors along with a VFD are very popular with knifemakers and their 2x72 belt grinders. Got the grinder, now I want to incorporate the motor along with VFD. Since I'm going the 3ph/VFD route plus have plenty of room for another 230 VAC circuit, I decided to go with the 2 hp.

3ph plus VFD allows you to vary the speed by quite a bit, very helpful when using differenty type belts on different type materials. Especially when you're trying to prevent an "Oh ****!" error on an almost finished knife.

Thanks,

My son has that exact same VFD for his 2x72 belt grinder. He has his wired to run on 120 volts. We have 220 volt outlet, but he has been happy with the 120 volt configuration.

 

[wyliesdiesels]

I looked at a bunch of them, but don't recall that one. I see the 6.8 now.

How does that impact the wire size?

Thats the only table for this 3ph motor

It doesnt impact wire size here in this case....

 

[FTG-05]

My son has that exact same VFD for his 2x72 belt grinder. He has his wired to run on 120 volts. We have 220 volt outlet, but he has been happy with the 120 volt configuration.

A lot of people do that, it's pretty much plug-n-play; just plug it in.

 

[FTG-05]

Thats the only table for this 3ph motor

It doesnt impact wire size here in this case....

My apologies, I wasn't clear. What does the table mean as far as wire size? Is it still 14 ga and/or 12 ga?

I'm sorry if I'm asking dumb questions, but this is one of those "can't fail - no fuzz on the peach" kinda operation.

 

[Aceman]

I'm not going to pick apart all the posts in this thread other than I'll mention most of them are wrong.

30 seconds of googling pulled up the manual for this vfd off galco.

https://www.galco.com/techdoc/kb/kbac-27dwhite_im.pdf

It has a 15 amp 230v 1 phase input to produce the full 2HP 6.7 amp 3 phase output.

The code requires wiring to be sized at 125% of the input current rating of a vfd. 430.122A

15 amps x 125%=18.75 amps rated wiring.

I would use #12.

 

[FTG-05]

I'm not going to pick apart all the posts in this thread other than I'll mention most of them are wrong.

30 seconds of googling pulled up the manual for this vfd off galco.

https://www.galco.com/techdoc/kb/kbac-27dwhite_im.pdf

It has a 15 amp 230v 1 phase input to produce the full 2HP 6.7 amp 3 phase output.

The code requires wiring to be sized at 125% of the input current rating of a vfd. 430.122A

15 amps x 125%=18.75 amps rated wiring.

I would use #12.

Page 13: Max Wire Size (Cu): 12 AWG.

Thanks!