Can 208V 3 phase run 220V 3 phase machine

[robertb671]

Hello, We're trying to diagnose why a test machine went down in our lab. The manufature has us doing some voltage checks and state the machine should run on 220v. In diagnosis we found that our building service is 208v. Since industrial electrical is far from my expertise, i'm trying to find out how much of a difference 208v is as compared to 220v. Not sure there is a simple answer with my lack on information! Anything would be helpfull at this time. Thanks

 

[dpc]

It will run, but not at the nameplate horsepower. If you try to draw rated torque/power from the motor it will probably eventually overload.

What is the nameplate voltage rating of the motor and what voltage was actually supplier at the motor terminals? A 208 V supply may only provide 200 V at the motor when voltage drop is taken into account.

 

[waross]

The standard motor voltage is 230volts. For years 230 volt motors were run on 208 volts. Machine manufacturers were well aware that 208 volts 3 phase was far more common than 240 volts 3 phase and sized their motors accordingly. In recent years there has been a trend to closer sizing and 200 volt rated motors are now commonly used on 208 volt systems.
Now given the sparse information you have provided we are assuming that you are talking about a motor.
What kind of machine is it?
Is it a motor?
What exactly does "went down" mean in this context?
Stalled, overheated, less than full stroke, blown fuses, burned out transformers, solenoids or motors?


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[rmw]

Or siezed up.....

rmw

 

[robertb671]

Hey guys,

The machine is a EMA dynometer (Elecro-Magnetic Linear Actuator). Basically the fuse box feeds power to the machines power enclosure. Within the power enclosure are 4 amps that feed the 4 actuators of the Dyno’s ram. The Dyno operated flawless one day, the next it would not operate.
We found all 3 70 amp fuses open circuit in the fuse box. Did a basic short to ground check at the box with negative results and installed 3 new fuses. As soon as we flipped the switch on, the fuses immediately opened. In contacting the manufacture, they insist something has changed. Like we moved the machine and miss-wired?
We are doing some step by step diagnosis with the manufacture at the moment. So far have disconnected the output connectors at the amp and checked resistance values between each phase of the motor coils. Which are to manufactures specs. The next step with be to disconnect input power to all the Amps, and then power them up individually to see whether the amps power up or not.
We don’t have schematics or current/amp specs etc. But the manufacture advised to power the amps using 220VAC and we’re running 208V. We didn’t want them to point the quick finger at the fact we’re using 208V. That was the purpose of the post…to get some feedback first.

Thanks again! This is actually becoming a cool learning exercise!

 

[ornerynorsk]

You are usually allowed +/- 10% on voltage for general purpose electric motors.

 

[waross]

220 volts is not a standard voltage. It was being phases out in North America about 60 years ago. I believe that with harmonization it is gone in IEC land also, but 220 is probably still used to refer to 230 volts.
The Point is;
What is the voltage rating on the machine and what is the frequency rating?
Is this North American made or European Union made?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

Taking a 230/240 volt system and running it on 208 could easily cause the issues you are seeing.

I would immediately install boost transformers.

Even if it actually runs it could have a shortened life. Like 50% its normal life. Is that worth avoiding the cost of three wall hung transformers?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Hi Keith. If you don't need a perfectly symmetrical neutral, two transformers works fine. I have had many occasions over the years to use a two transformer boost on three phase and have never had an issue.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

I've never had the guts to try that.. LOL

Keith Cress
kcress -

http://www.flaminsystems.com

 

[7anoter4]

If this motor is manufactured according IEC-34-1 then use of a 220-230 V rated induction motor at 208 V[0.945 voltage p.u.] is boundary permitted be IEC 34-1.But, using 50 Hz rated motor at 60 Hz [1.2 frequency p.u.] is not recommended at all. The problems will be, mainly, the losses. Iron losses will grow 50% and copper-due to elevated skin effect. The bearing losses will increase also. The leakage reactance will increase 20% and the torque will decrease.

 

[rbulsara]

robertb67:

The problem you described, 3-70A fuse blowing, indicates there is dead 3 phase short or extreme overload ( machine is jammed). 208V instead of 220V would not be the cause of 3-70A fuse blowing.

Find the cause of th eovercurrent. Did this machine ever worked other than the one day you mentioned? How old is it?

 

[gmacCAN]

This is a common problem for me investigating power quality problems for a utility

In Canada we supply many larger commerial buildings with 347/600V voltage and the building owners use their own step down transformers to provide their tenants 120/208V and in most cases it works very well. Smaller buildings may have 120/208V main supply from us

Problems are now occuring when globalization is forcing manufacturers to to create 1 piece of equipment that will function at 208,230,240V and it comes with a name plate voltage of 220V. A large well known food chain now has all new equipment rated at this voltage including bun toasters

CSA Standard CAN235 states that the voltage should be maintained between 94-105% or low voltage of 196V. Equipment now rated at 220 V is trying to operate at 89% of its nominal voltage (utilization voltage can be even lower). It is amazing how much slower the buns toast at peak time around dinner when the utility voltage is at its lower levels.

We now see more printing equipment,gas station fuel pumps, HVAC equipment with this nameplate voltage being used on 3-phase and 240 single phase supply voltages and they are failing or burning out

We now tell customers with 600V to contact their vendor and possibly look at installing drycore transformers to match the voltages specifically for these loads

208V customers have to look at more epensive options. Equipment owners have to look more closely at this problem before the equipment is installed and put into service

 

[itsmoked]

gmacCAN; Yep! We have seen this for years in refrigeration. Compressors with 230V motors installed into 208V service - fail early - always !

Half the time 208 is only really 19x anyway.

rbulsara; It could be that the machine has stalled and so those fuses are going on each start attempt.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[rbulsara]

I find it hard to believe that 208V did it. There was something else wrong with the machine.

 

[ScottyUK]

My interpretation of the OP was that the 208 / 230V is the supply into some sort of servo amplifiers and the motors are connected to the output of the servo amp. If that is the case then it renders some of the discussion above irrelevant in this context, if still technically correct. Perhaps robertb can clarify the configuration of his equipment?


----------------------------------

If we learn from our mistakes I'm getting a great education!

 

[jasonf987]

Just keep in mind that no equipment will have it's "specified" power at all times. your supply will always fluctuate within certain tolerances due to a number of reasons. I tend to agree with rbulsara, on the limited info available it would seem that there is something else at fault. speak to your supplier and ask him across which range his equipment can operate, if all else fails check the operating manual for any technical info available.

 

[jraef]

I'm totally with ScottyUK here. I also saw that he is discussing AN amp, not THE amps. Sounds to me as though it is an amplifier of some sort, probably a servo. Keep in mind, the OP is not an EE, so he may not know what he is looking at.

robertb671,
Please post the motor nameplate information, and if not accessible, a better description of what you have. If by "amp" you mean an amplifier, then all of the discussions about motor voltages are essentially moot. But low voltage may in fact still be an issue for you, just for different reasons. In powering a servo, the AC power must be rectified to DC (that s what the "amp" does). In that process, there is usually a short surge of current as the DC bus is charged. But since you are only feeding it 208V, the lower voltage will result in higher input current and is possibly exceeding the instantaneous rating of your fuses.

Another possibility is that you have the wrong type of fuse. If the equipment was made in Europe or some other IEC country, the types of fuses they use are difficult to attain here in the US (assuming you are here because of the 208V supply) and your electrician may have not carefully investigated the fuse type he should use; happens quite a lot actually. Look at the numbers on the fuse and post them, then find out what specific fuse the manufacturer says t use. Some of us will be able to tell you if you have the right kind or not.


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[stevenal]

As jason said, the supply will fluctuate. ANSI C84 gives the allowable ranges. The A range minimum utilization for 208 is 191. The B range ("limited in extent, frequency, and duration") is 184. These are below what many 230 rated devices will accept.