Voltage

[MF294-4]

Can I run a 208 volt saw on 240 without getting a transformer? Factory is selling a 208v single phase saw. Cant determine if the motor is multiple voltage.

 

[Billy Shafer]

Save your money.

 

[MarkB_MI]

208 volts is the phase-to-phase voltage for 120 volt wye three-phase. Very commonly used by the military. You can probably get away with running a 208 volt tool on 240, depending on the tool and the type of motor it has. What sort of saw is it?

 

[Steve@Advance]

Yes, it will work on 240v.

 

[John T]

Yes, in my professional opinion (still subject to the actual motor specs) you can power a motor labeled 208 Single Phase using 240 Volt Single Phase WITHOUT ANY VOLTAGE REDUCING TRANSFORMER, I often saw that done over my many years in power distribution. I would be MORE concerned if you wanted to use 208 to power a 240 motor, but that can also work. I wonder as you mentioned the motor is LABELED DUAL VOLTAGE 208 or 240 ??? Typically for some more INDUSTRIAL power distribution I specified 240 or 480 Volt Three Phase Three Wire Delta, while for RETAIL or OFFICE retail I specified 208 Y 120 Volt Three Phase Four Wire where I had three legs of 120 VAC Single Phase for the office/retail with 208 Volt Three Phase used for HVAC.

John T Retired n rusty on this but believe its still accurate, if in doubt when it comes to fire or life safety DO NOT take my word for it, consult the NEC and current trained professional electricians and engineers.....

 

[dr sportster]

That is not far off enough to matter.208 will work fine on 240 v.

 

[MF294-4]

Its a Scotchman cold cut saw. Intermittent run.

 

[MarkB_MI]

> Its a Scotchman cold cut saw.

WHOA! Are you sure that is NOT a three-phase motor on that saw? The Scotchman site lists only 220V as the single-phase option, while there are several three-phase options, including 208V. Unless you have three-phase power in your shop, you probably don't want a three-phase saw.
Scotchman cold saws

 

[John T]

Do you have the model number??? Or the nameplate which shows voltage ?? If so we may be able to help more

John T

 

[kencombs]

Probably intended to ge used in a building with 240v/3ph/high(or red)leg service. Mine is like that. 3 conductors, 2 each 120v to ground 1 208 to ground and a neutral. Provides 240/3ph, 240/1ph and 120v/1ph. And the 208 for a saw like that one.

 

[John T]

From what you say and not being there I don't know exactly for sure what electrical service you have, but when you say there's 2 with 120 to ground and one with 208 to ground, THAT SOUNDS AS YOU INDICATE WHAT I CALL 120/240 VOLT THREE PHASE FOUR WIRE RED/HIGH LEG 2 DELTA. HOWEVER when you say

208 for a saw like that one

(if its indeed 208 SINGLE PHASE ??) even if there are 208 L2 Red/High to Neutral, thats NOT any use I specified even if it can work, but hey different methods for different folks !!

FYI here are a couple options regarding 208 volt and 240 volt which may help you figure out 1) Just what power you have available and 2) Based on the motors model number and/or the voltage nameplate what it requires to run:

A) One typical (more office and light duty versus heavy industrial) electrical service is:

208 Y 120 Volt Three Phase Four Wire. Its three Line conductors, L1 L2 L3, would read 120 Volts any of the three to Neutral........There would be 208 Volts any Line to any other Line......You could get 208 SINGLE PHASE any Line to any other Line............You could get 208 Volts THREE PHASE using all three lines L1 L2 L3

B) SOUNDS LIKE YOURS: 120/240 Three Phase Four Wire (Red/High/L2) Leg Delta: You would get 240 Volts SINGLE PHASE any L to any one other L..........You would get 240 Volts THREE PHASE using L1 L2 L3......There would be (I NEVER in my years in Power Distribution designed or specified any such use of the Red/High L2) 208 Volts from the Red/High Leg L2 to Neutral.........There would be 120 Volts from L1 or L3 to Neutral.....

Once you know for sure WHAT POWER YOU HAVE AVAILABLE and the Voltage and Phase (single or three) of your saw we can figure this out

Hope this helps, post back more info and any questions

QUESTION Did any other of the professional electricians on here see the Red/High L2 Leg used much for a 240 Volt Single Phase motor ????????????

John T Long retired n rusty power engineer so no warranty, but believe this remains true today.

 

[John T]

OOPS MY Bad, I replied in the wrong box below, so I will repeat it here, even if it doesn't apply to YOUR SITUATION it may still help:

From what you say and not being there I don't know exactly for sure what electrical service you have, but when you say there's 2 with 120 to ground and one with 208 to ground, THAT SOUNDS AS YOU INDICATE WHAT I CALL 120/240 VOLT THREE PHASE FOUR WIRE RED/HIGH LEG 2 DELTA. HOWEVER when you say
208 for a saw like that one (if its indeed 208 SINGLE PHASE ??) even if there are 208 L2 Red/High to Neutral, thats NOT any use I specified even if it can work, but hey different methods for different folks !!

FYI here are a couple options regarding 208 volt and 240 volt which may help you figure out 1) Just what power you have available and 2) Based on the motors model number and/or the voltage nameplate what it requires to run:

A) One typical (more office and light duty versus heavy industrial) electrical service is:

208 Y 120 Volt Three Phase Four Wire. Its three Line conductors, L1 L2 L3, would read 120 Volts any of the three to Neutral..... ..There would be 208 Volts any Line to any other Line..... You could get 208 SINGLE PHASE any Line to any other Line..... ..... You could get 208 Volts THREE PHASE using all three lines L1 L2 L3

B) SOUNDS LIKE YOURS: 120/240 Three Phase Four Wire (Red/High/L2) Leg Delta: You would get 240 Volts SINGLE PHASE any L to any one other L..... ....You would get 240 Volts THREE PHASE using L1 L2 L3..... There would be (I NEVER in my years in Power Distribution designed or specified any such use of the Red/High L2) 208 Volts from the Red/High Leg L2 to Neutral..... ...There would be 120 Volts from L1 or L3 to Neutral.....

Once you know for sure WHAT POWER YOU HAVE AVAILABLE and the Voltage and Phase (single or three) of your saw we can figure this out

Hope this helps, post back more info and any questions

QUESTION Did any other of the professional electricians on here see the Red/High L2 Leg used much for a 240 Volt Single Phase motor ????? ?????

John T Long retired n rusty power engineer so no warranty, but believe this remains true today .

 

[MarkB_MI]

John, I don't think the OP ever said he has three-phase power of any sort.

 

[drummer481]

I was always taught + or - 10%, so thus in effect this motor would be looking for anywhere between 187.2 VAC to 228.8 VAC to operate efficiently...................

 

[MF294-4]

All I am going on is he advertised it as 208v single phase and he has not returned any answers yet. I do have a 240v rotary phase. Converter.

 

[MarkB_MI]

> All I am going on is he advertised it as 208v single phase and he has not returned any answers yet. I do have a 240v rotary phase. Converter.

Well, if it's a used unit anything is possible. If it's a new unit, maybe it was a special order that was never delivered. 208V single phase is not common but is certainly possible. Since you already own a phase converter, I'd go for it; if it turns out to be a three phase unit you're already set up for it.

The thing about ac induction motors is they will draw whatever current they need to do the job. It's current that delivers the torque, not voltage. And it's the load that determines how much torque is required. It's better to have too much voltage than not enough, since the greater the voltage the easier it is for the motor to draw however much current it needs. You should be fine running a 208V cold saw on 240 volts.

 

[John T]

For the time being you can only take him at his word, but can also prepare in case its NOT what he says.

That being said:

1) If it's actually 208 Single Phase ? you can power it using 240 Single Phase.

2) If it turns out 208 Three Phase (better actually), you already have that rotary phase converter.

Once you see its actual voltage and phase, you can wire it accordingly. Don't forget to provide the proper, Means of disconnection, Overcurrent and Thermal Protection. I often specified a Combination Starter in such cases.

It sounds like you have standard 120/240 Volt Single Phase Three Wire distribution ?? which should be adequate based on your total loads

Let us know how it works out and post back any questions...

Have a great day everyone

John T

 

[John T]

Thats correct, as I explained I posted my response in the wrong box grrrrrrrrr

Best wishes

John T