Where do I put the neutral? Quincy QT 220 1 phase
- Thread starter jomobco
- Start date
Shock-Therapy
New member
- Joined
- Nov 30, 2013
- Messages
- 2
Cap it.
Charles (in GA)
Well-known member
The receptacle you show is two hots and a neutral, with no provisions for a ground. Grounds are D shaped pins, never flat.
Second, If the compressor has a motor starter (you show pics of one) it is at least five actual horsepower. That plug, or just about any plug you will find (other than expensive sleeve and pin setups) will only have a horsepower rating of no more than 3 hp.
Third issue is the connections in the starter relay are most likely not designed for the fine stranded wire used in CORD (as opposed to the course stranding used in stranded WIRE such as THHN. There is a difference.
You should be hardwiring the compressor using THHN wire in a flex conduit of some sort, to a junction on the wall or a disconnect.
You are required to have a disconnect in line of sight of the compressor and no more than 50 ft from the compressor.
Charles
edit: if you were to use a receptacle, here is what it would look like. NEMA 6-50 rated for up to 250 volts.
Be aware that there is a NEMA 5-50 which is a 125 volt plug and receptacle, which looks like this, just that the wide and flat blade positions are reversed and The wide blade is a gray or silver (denoting neutral).
Second, If the compressor has a motor starter (you show pics of one) it is at least five actual horsepower. That plug, or just about any plug you will find (other than expensive sleeve and pin setups) will only have a horsepower rating of no more than 3 hp.
Third issue is the connections in the starter relay are most likely not designed for the fine stranded wire used in CORD (as opposed to the course stranding used in stranded WIRE such as THHN. There is a difference.
You should be hardwiring the compressor using THHN wire in a flex conduit of some sort, to a junction on the wall or a disconnect.
You are required to have a disconnect in line of sight of the compressor and no more than 50 ft from the compressor.
Charles
edit: if you were to use a receptacle, here is what it would look like. NEMA 6-50 rated for up to 250 volts.
Be aware that there is a NEMA 5-50 which is a 125 volt plug and receptacle, which looks like this, just that the wide and flat blade positions are reversed and The wide blade is a gray or silver (denoting neutral).
Last edited:
You have not provided good information. Please refrain from doling out bad electrical advice. PLEASE!
Pay attention, The OP was just posting the receptacle he was planning to use.
lg
no neat sig line
Charles (in GA)
Well-known member
The max hp rating is given in THIS DOCUMENT and is listed as 3 hp (specifications for the Hubbell plug I show a pic of.)
For the receptacle, THIS DOCUMENT lists the hp as 3 hp max.
You have to go to some extraordinary expensive plugs and receptacles to get higher HP ratings.
Charles
For the receptacle, THIS DOCUMENT lists the hp as 3 hp max.
You have to go to some extraordinary expensive plugs and receptacles to get higher HP ratings.
Charles
Aceman
Well-known member
Over here you have to verify with the power company if it's okay to use such a large single phase motor. Here are the notes from each of their service requirement manuals, PPL first:
Consult the Power Company regarding the use of motors rated above 3 horsepower. Motors above 3 horsepower have special requirements
From UEC's manual:
Customers connecting any individual motor larger than five horsepower must obtain prior approval in writing from the Power Company. In addition, air conditioners and heat pumps larger than five tons require prior Power Company approval.
Single phase motors larger than three horsepower may cause voltage dips
objectionable to some Customers.
Consult the Power Company regarding the use of motors rated above 3 horsepower. Motors above 3 horsepower have special requirements
From UEC's manual:
Customers connecting any individual motor larger than five horsepower must obtain prior approval in writing from the Power Company. In addition, air conditioners and heat pumps larger than five tons require prior Power Company approval.
Single phase motors larger than three horsepower may cause voltage dips
objectionable to some Customers.
kaffine
Well-known member
I guess it is a good thing all of my large motors are 3 phase running off my phase converter otherwise I would be in trouble.
Guess again
The phase convertor makes this problem worse not better. You have to ADD the phase convertor's running current on to the amp load of the motor!
My Commercial service has a 20 hp max motor starting limit w/o soft start. The engineer at the power co. said that they could see the loading on even a 5hp motor starting from their end at the substation.
William....
kaffine
Well-known member
Sorry I forgot the 
I know running a phase converter doesn't help.
However running them from my generator does.
I know running a phase converter doesn't help. However running them from my generator does.
myfinishingtouch
Well-known member
- Joined
- Aug 23, 2013
- Messages
- 52
The previously attached document listed the plug as rated at 50 amps but only for a 3 hp motor. I'm very confused. I'm fixing to wire up a 7.5 hp 3-phase bandsaw that needs 30 amps. Is it the amp rating of the plug or the hp rating of the plug that determines what can be hooked up by it?
Thanks,
Dave
Thanks,
Dave
hidollartoys
Well-known member
It is not that they CAN , but they DO experience this large in-rush. ALL electric motors exhibit this. This is why the NEC has VERY specific branch circuit and associated OCPD sizing for electric motors.
laser3kw
Well-known member
had to google that
it's Overcurrent Protection Devices not Obsessive–compulsive personality disorder
but I guess the second may have relevance to the NEC code
No problem if you are running 480V.
The HBL2731 NEMA L16-30p is rated at 10hp. Otherwise at 30 amps as far as I know your sol.
Both, for Motors the hp rating is used and for Non motor loads the amp rating is used.
William....