To avoid these ads, REGISTER NOW!

Wire Size for Static Phase Converter

B

bczygan

Well-known member
Joined
Nov 4, 2009
Messages
22,002
Location
DETROIT! Arsenal of Scrappers
Under 50' wiring.

1-3HP Static Phase Converter 220V single phase to three phase
Phase-a-matic PAM-300HD

Serving 2HP three phase Bridgeport (Chinese motor).

How do you calculate?

Bill
 
Last edited:
To avoid these ads, REGISTER NOW!
L

larry_g

Well-known member
Joined
Apr 28, 2007
Messages
16,877
Location
oregon
Last edited:
OP
B

bczygan

Well-known member
Joined
Nov 4, 2009
Messages
22,002
Location
DETROIT! Arsenal of Scrappers
larry_g said:
I would size the wire serving the static converter as if it were a 3 hp single phase motor, Max rating of the converter.

http://groverelectric.com/assets/do...ate Wire & Fuse Sizes for Electric Motors.pdf

Per the chart above 25 amp draw, 35 amp fuse, 10g wire.

On edit , Phase a matic instructions are here; http://www.phase-a-matic.com/PDF/SIS.pdf

Remember that you have to size the 240v feed size to handle the ALL the current.

lg
no neat sig line
Click to expand...

Why?

It's a 2HP 3 phase motor!

Don't I need to only take into account the inrush current on startup and then figure the running amps for a 3PH motor?

15A? 20 at the most?

Bill
 
L

larry_g

Well-known member
Joined
Apr 28, 2007
Messages
16,877
Location
oregon
bczygan said:
Why?

Max rating of the converter.

It's a 2HP 3 phase motor!

Don't I need to only take into account the inrush current on startup and then figure the running amps for a 3PH motor?

15A? 20 at the most?

Bill
Click to expand...

I said the max rating of the CONVERTER. Right now your only looking at the onel load you may use now. What is the next load your going to try to run? Got a lathe yet? It may be a 3hp. So take the high road.

You are driving a 3 phase motor with the converter but you have to figure the current for the hp being used on the SINGLE PHASE LINE. So if you look at the linked chart even a 2hp motor is 20 amps and a 25 amp fuse.

The motor side of the converter you can figure the wire size per the 3 phase charts. Power in a 2hp motor is the same if single or three phase, but the current draw is not.
 
W

wyliesdiesels

Well-known member
Joined
Aug 14, 2012
Messages
20,002
Location
Modesto, CA
larry_g said:
I said the max rating of the CONVERTER. Right now your only looking at the onel load you may use now. What is the next load your going to try to run? Got a lathe yet? It may be a 3hp. So take the high road.

You are driving a 3 phase motor with the converter but you have to figure the current for the hp being used on the SINGLE PHASE LINE. So if you look at the linked chart even a 2hp motor is 20 amps and a 25 amp fuse.

The motor side of the converter you can figure the wire size per the 3 phase charts. Power in a 2hp motor is the same if single or three phase, but the current draw is not.
Click to expand...

The directions say to size the breaker (and thus wire) at double the amperage rating of the motor.

So OP what is the FLA on the motor nameplate?
 
L

larry_g

Well-known member
Joined
Apr 28, 2007
Messages
16,877
Location
oregon
bczygan said:
Guy at Phase-a-matic thought 15A based on 2HP 3PH draw fed with 240V 1PH.

Chinese 2HP 2 speed motor with faceplate wiped clean.

Bill
Click to expand...

Well according to this, http://www.elec-toolbox.com/usefulinfo/flamtrcharts.htm , I would concur. However I would still wire it for a 3 hp load. Plan ahead man, plan ahead. I would also configure it with the rotary motor. I have had a rotary converter in my shop for years and it just plugs along powering all the 3p stuff in my shop.

lg
no neat sig line
 
To avoid these ads, REGISTER NOW!
OP
B

bczygan

Well-known member
Joined
Nov 4, 2009
Messages
22,002
Location
DETROIT! Arsenal of Scrappers
larry_g said:
Well according to this, http://www.elec-toolbox.com/usefulinfo/flamtrcharts.htm , I would concur. However I would still wire it for a 3 hp load. Plan ahead man, plan ahead. I would also configure it with the rotary motor. I have had a rotary converter in my shop for years and it just plugs along powering all the 3p stuff in my shop.

lg
no neat sig line
Click to expand...

Yeah, I'm thinking 30A breaker and #10 so I could use the circuit for a compressor?

OTOH, I'm in a 1 car garage and everything is close and plenty of panel spaces (30/40).


Bill
 
N

Norcal

Well-known member
Joined
Mar 16, 2008
Messages
13,754
bczygan said:
Yeah, I'm thinking 30A breaker and #10 so I could use the circuit for a compressor?

OTOH, I'm in a 1 car garage and everything is close and plenty of panel spaces (30/40).


Bill
Click to expand...

Not a good idea, a static converter just starts a 3Ø motor then it single phases the motor, which means you lose 1/3 of the motors HP rating make it a very bad choice for a compressor, but IMO it's a bad choice for any motor.
 
OP
B

bczygan

Well-known member
Joined
Nov 4, 2009
Messages
22,002
Location
DETROIT! Arsenal of Scrappers
wyliesdiesels said:
As in use the static converter to power a compressor?
Click to expand...

No, as in have a circuit run, that could be used for other purposes later.

But I'm thinking, why not just run the circuits I need, when I need them. The panel and feed will be adequate, so no need to plan alternate uses for this circuit. It won't even be where I could put a compressor or welder. What other reason would there be to up size? To accommodate a conversion to a rotary phase converter?

Bill
 
Last edited:
M

matt_i

Well-known member
Joined
Mar 14, 2008
Messages
10,726
Location
SE Michigan
Not mentioned is the HP or FLA of the compressor, so its not known if #10 could work.

Along the lines of an unknown 2hp x 750W/hp x 125% / 240vac = 7.8A

Upsize to 2hp x 750W/hp x 200% / 240vac = 12.5A both within the limits of #14 awg.

But, as mentioned, not worth it to have to do it again later, buy another circuit breaker, pull more wires in a stuffed conduit....

While not specifically code due to phase-taping less than #6 awg, you could buy a single spool of #10 THHN and run EMT or PVC conduit, identify the phases with tape or heat shrunk labels. 3 phase devices connected to 4 conductor NM wire makes my head explode :yikes:
 
Last edited:
OP
B

bczygan

Well-known member
Joined
Nov 4, 2009
Messages
22,002
Location
DETROIT! Arsenal of Scrappers
nine4gmc said:
Any reason for not running a VFD on that thing Bill?
Click to expand...

Hi 9's!

Good to see you posting all around. Let's you give your mind a break from "The project".

A VFD?

Funny you should ask.

There's one sitting right in front of me. Sized and bought for this. But I'm such a duffus, that I can't figure out how to hook it up.

The static converter works fine. and I have it hooked up with #10 temporarily, but it's time to wire it properly from the sub.

I do want to put in some kind of a switch, so it doesn't run continuously, or require me to use the breaker to turn it on and off. What kind of switch should I use? Should it be fused?

Bill
 
Last edited:
M

matt_i

Well-known member
Joined
Mar 14, 2008
Messages
10,726
Location
SE Michigan
A static phase converter is just a start capacitor thats temporarily switched between L1 and L3 or L1 and L3. So there's not much harm in letting it sit there electrified.

* could also be a run cap to attempt to balance voltage on the L3 generated leg but the balance changes with load...so...it doesn't do much good.
 
Last edited:
You must log in or register to reply here.
To avoid these ads, REGISTER NOW!
Top Bottom