Run the Motor Without Having Name Plate Details?

I don't know, try connecting it to a Variac and gradually increase the voltage. It will either:

A/ run

B/ smell like burnt ****

C/ catch fire

Let us know how it is.

I would start by measuring the motor and correlating its dimensions to a motor frame table such as NEMA. This would give some idea of the possible voltage/horsepower combinations. Then you could try starting it at the lowest reasonable voltage, with no load attached. If it starts sluggishly, try the next higher voltage, etc. Measure the current to see what it matches up to.

Then add some load, continuing to monitor the current, and also the motor temperature. A tachometer would be handy; by knowing the rpm, you can compare with standard speeds and see what the slip is. With some experimentation along these lines, you should be able to "home in" on what the motor can do.

Even if the name plate is there reqirement of codes as well as standard practice is to mark it safe by insulation resistance test (meggar) and grounding test.

Similarly the codes also require a motor to be tested initially at No Load for two hours before putting in service.

With the name plate missing prime uncertainity can be the applied voltage and the frequency, here some approximations and experience counts;

Take dc resistance measurement of winding, momentarily switch on the supply and check current, rpm and temperaure rise, compare results with simlar frame size motors.

OK if we've got to be sensible about this.

We're assuming it's 3 phase. Our guest's country of origin will have 1 or maybe two 3Ph distribution voltages. After testing the motor for continuity and insulation:

A/ if possible connect in star and connect to lowest supply voltage available. If it runs keep it running. Monitor the temperature and current over a period of hours

B/ if it doesn't run try the next higher voltage. Monitor as before.

C/ if it still doesn't run go back to the lower voltage and connect in delta. Monitor as before.

D/ if it still doesn't run go to the higher voltage. Monitor as before.

E/ if it still doesn't run put it back in the skip you found it in.

From the current and RPM and frame size measurements it should be possible to track down the rating.

Frame size:

Shaft diameter

Shaft height from bedplate

Dimensions of mounting bolts

Follow these steps:

(1) You first need to identify the voltage of the motor (Low voltage or Medium Voltage). You can find it by looking into the motor terminal. By looking the motor terminal, an expert electrician can find it easily.

(2) Identify the number of phase by looking into the number of terminals or the number of leads. An expert electrician can do it easily.

(3) Measure the RPM of the motor running the motor with no load. Yu can use tachometer to measure the RPM.

(4) Find the motor KW. See the thread to find the KW: http://cr4.globalspec.com/thread/43648.

Hope it helps.

- MS

The most likely way for an electrician to identify the motor by simply looking at it and recognising the manufactures motor body style. Manufacturers have their own little design quirks. From there it's a case of looking at frame sizes.

Shaft diameter is a clue. Fractional HP motors will usually be 1/2" or 5/8" diameter. You can tell a lot about a motor by referring to a NEMA chart which gives all the dimensions. The number of wires will tell you whether it is single phase, 3-phase and/or dual voltage.

What do you mean by "safety region"? Are you asking if an unknown motor can be run in a location where flammable gases or dust is present?

If so, no, the motor must be certified as explosion proof for the specific location.

"general purpose" equipment can be run in hazardous areas by purging and other means. However, regulations are country/location specific, so you need to consult with your safety guy.