Question on 220v outlet.

SkagSig40

SkagSig40

Joined
Feb 1, 2001
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2,671
Hi guys, I'm on my way to grinding some steel! Do you guys think I might have any trouble with this set up? My Father in law is good with electricity and wired his whole house himself and helped me install my 220v outlet for my grinder. I am just about out of spots/room in my SquareD cricuit box in my basement so I have to run a few different pieces of equipment off of one outlet. We installed a 220v 30amp circuit and I plan on using the grinder which draws 10 amps and my welder that would draw the most of all my equipment at 22 amps. The welder has the big dryer type plug on it so I'll have to wire the grinder motor to fit the dryer plug.My Father in law said this should work for both and any other 220v equipment that draws less then 30 amps I might use in the future. Do you see any problems with this set up we might have over looked? Thank you for any help!:)
 
Assuming it is wired correctly, the only problen I could see, would be that you are UNDER protecting the grinder and welder. If something happened with the grinder, it would not trip the breaker, and serious damage could be the result(to the grinder). Same with the welder.
With that said, I have a similar setup. I've got to change those breakers one day.;)
 
I know absolutly nothing about electricity. How would I protect the grinder and welder fully and still be able to use them both on the same outlet? If I used them like this what could go wrong to cause damage to the them?
 
What I am referring to is the circuit breaker. You say you have a 30 amp circuit, and your grinder puts out only 10 amps. If you get a short, or something else in the motor to cause an electrical malfunction, before that 30 amp breaker shuts off, you will do irreperable damage to the grinder motor. You can probably put an inline 10-15 amp fuse on the grinders plug line, same with the welder(25amp), although the welder is a lot closer to 30 amp than the grinder.
I am just referring to a worst case scenario. You can run the grinder and welder on that line, and chances are, nothing will happen. Like I stated, I run my grinders on the same type of line, I can't change to a lower amperage breaker, as I have a 2HP milling machine that pulls at least 25 amps using the same circuit. So I just take my chances with the grinders, although mine do have internal fuse protection as they are DC variable speed.
I'm just nit picking here. Go use your grinder.:D
 
Hello

Your grinder motor may be rated for 10A continuous but the starting surge current may be considerably higher than that. I have heard of starting surge currents of up to 6X the continuous rating, if the motor is started under full load. Your grinder should not present such a heavy load on start-up, but the inertia of the motor itself and all the rotating parts of the grinder will present a non-trivial load. It is likely that the start-up surge current at least as high as the continuous rating in your application. If you change to a breaker that has too low a capacity, you may start to get nuisance trips and you will not get the motor started. Check with someone who sells the kind of motor that you have to see what their recommendation is.

There may be a similar start-up surge current for your welder too. I am presuming that you will only be running your grinder or your welder at any one time.

Hope this helps.

Phil
 
Thank you very much Mike and Phil! The guy at Home Depot said it really shouldn't make a difference if I ran the motor on this circuit as most house hold lamps and hair dryers ect. only draw an amp or 2 and the circuit is usualy 15-20 amps and that does not fry them. Man this stuff can be a pain in the you know what!:D
I have not bought the motor yet but I think I might get a Leeson 2hp and the seller said it would draw 10 amps at most on start up.
Thanks again for any and all help/info!!:D
 
Motors can get very confusing in a hurry.

Formally, motors require 2 types of protection:

1. short circuit
2. thermal overload


Because the normal start-up current can be very high, the fuses/ circuit breakers used to protect the wiring need to be over sized to reduce a nuisance fault from starting the motor. Since the fuse/cb is oversized, the motor is unprotected from prolonged over current. The motor will heat up and could be damaged. This is where the thermal protection comes in. This is slow tripping feature that needs to trip at lower current levels but requires an extended time before it activates so that it doesn't prematurely kick-out during start-up. Not good for short circuit protection since it takes time to activate.

The Leeson 2hp motor has a name plate rating of 9.2A @ 220V. This is the full load amperage....not the start up amps. The actual "starting-amps" will vary based on the machine and how inertial load needs to get moving. A motor without anything mounted on the shaft will start will less current than a motor with a flywheel on the shaft. With this in mind, it is difficult to predict the starting current. For a belt grinder....no issue.

Anyway, there are some fuses specifically designed to offer both types of protection for motors. They have dual elements, 1 for short circuit, and the other for thermal over load. When they blow, they have different indicators based on the type of failure.

As far as the Leeson 2Hp and your grinder goes......your in luck! That particular motor has thermal protection built in. It is a manual reset button on the front of the connection box. So all you need to do is wire the motor with conductors rated for 30 amps (circuit breaker size) and your set. From there the motor will protect itself. Plug it in and start grinding!.....I love these Leeson motors!

Good luck,
Rob
 
ran the motor on this circuit as most house hold lamps and hair dryers ect
Click to expand...

Acutally hair dryers (1200 watts) draw near 10 amps, also you will probably give any computer in your house fits.
 
Originally posted by DaveH
Acutally hair dryers (1200 watts) draw near 10 amps, also you will probably give any computer in your house fits.
Click to expand...

Hi Dave, What do you mean by "...will probably give any computer in your house fits"?

Thank you again Rob! The last thing I want to do is ruin my motor/equipment as soon as I use them the first time! :eek: That would be an expensive mistake! When I finally buy the Leeson I think I will bring it to Home Depot and have the eletrical guy help me wire it safely!

Man, all I want to do is make some knives!:p :D
 
What I mean is that if you have a computer that's sensitive to fluctuating power, like say an old power supply, then introducing 10 + amp transient loads will probably cause a voltage sag in your house.

You might want to keep the computer turned off while you're working.

Just as an example, I run on a UPS for the computer and a couple of days ago it beeped and kicked in about 5 different times in the afternoon, and that was when the neighbor turned on his 220 v table saw next door. ( I suppose I should call the power company about that.)
 
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