Changing the motor voltage to 220 V AC

[rock_breaker]

I have a Enco 105 111? mill/drill and am considering changing the power in put from 110 V AC to 220 V AC . Is there any thing more to change than the 2 jumper bars in the power box on the back of the machine? It does have a reverse switch and will run counter clockwise when the switch is thrown. All help will be appreciated.
Ray

 

[mksj]

This was reviewed in a previous thread:

Enco 105-1110 rf-30 convert to 240v...

My Enco mill came to me wired for 115v. I have 204v available so I'd like to rewire it to take advantage of that. Problem is, it doesn't appear that the wiring listed inside the motor box cover is wired exactly like it shows in the diagram. Can someone help me with how to properly make this...

www.hobby-machinist.com

 

[markba633csi]

Hi Ray, take a look at that other thread, let us know if you need more info or it doesn't match your machine
Mark

 

[stioc]

Is there an advantage to switching to 220v vs 110v? I'm asking because I have the same mill currently wired for 110v. I would love to have speed control via a VFD but that requires a 3-phase motor.

 

[Karl_T]

1 hp and under 110 is fine.
2 or 3 hp 110 will work, not advised.
over 3, you need 220.

Current is 1/2 as much on 220.

 

[stioc]

@Karl_T thanks, I'm just trying to understand the whys. So why is it that 2-3hp are not advised on 110v?

True the current is half on 220 but the watts consumed are the same. So is the advantage just that you can run bigger motors without running heavy gauge wiring and breakers as would be required for 110v to handle the amperage?

 

[Latinrascalrg1]

Running on 220v instead of 110v will pull less amperage which means less heat which is easier on the electrical components along with more cash in your pocket because it is a bit cheaper to run.

 

[stioc]

Running on 220v instead of 110v will pull less amperage which means less heat which is easier on the electrical components along with more cash in your pocket because it is a bit cheaper to run.

OK the less heat part (from fewer amps) makes sense. However, 220v being cheaper I believe is a myth because as I mentioned earlier the wattage is the same. My power company charges by KWh.

 

[Latinrascalrg1]

Less energy lost through the extra heat is proof of the savings if you really think about it. Its not a huge amount thats hardly worth mentioning and personally I believe the true value to be in the long run aspect of it being easier on many of the electrical components......at least thats what I have deciphered thru my learning process......

 

[WCraig]

I am not an electrician, but...

In round numbers, and many motors are different:

a 1 HP motor requires 15 amps at full load on 120 volts or 7.5 amps on 240 volts
a 2 HP motor requires 30 amps at full load on 120 volts or 15 amps on 240 volts
...

A standard household 120 volt circuit is sized for a max 15 amp load. But electrical motors briefly suck up much more current when starting. Therefore it is recommended to ensure that the circuit can supply 20 to 25% more amps than the full load requirement for the motor. So, right there, a standard household circuit is inadequate for a 1 HP motor. Do people run 1 HP motors on 15 amp circuits? Yes. But it is cutting into the safety margins. You should always assume that your wiring was done by some kid who was hung over from last night's party. All too often, that's literally true. Overheated wiring can lead to a fire and that is generally not a desirable outcome.

Can you put in higher amperage household circuits? Sure, but the wire in the wall has to be a sufficient gauge to carry the current. Note that the same wire gauge can carry the same amount of amperage regardless of the voltage. Thus, if you are going to run wire through the walls to power a motor, you can safely use smaller gauge wire to power the motor at 240 volts. That saves money.

Craig
PS I don't believe that electric motors are generally more efficient on 240 v. 120 volts. But that is even further from my field of expertise.