MOTOR OR GENERATOR??
MOTOR OR GENERATOR??
(OP)
A customer brought in a motor for repair. It is a 3 phase motor 2 pole 400 volts off a refrigeration unit of a lorry. The customer says it is a generator.The motor has a rotor and is connected star on the terminal block.When i power the motor it runs at the rated speed.So why does the customer say that it is a generator which is run by an engine???





RE: MOTOR OR GENERATOR??
RE: MOTOR OR GENERATOR??
Induction generator? coustomer says it powers two fan units.
I am still puzzled...
RE: MOTOR OR GENERATOR??
RE: MOTOR OR GENERATOR??
RE: MOTOR OR GENERATOR??
Quando Omni Flunkus Moritati
RE: MOTOR OR GENERATOR??
RE: MOTOR OR GENERATOR??
Actually, as I review the original post he never says. Sorry, not enough info to go any further with this really.
Quando Omni Flunkus Moritati
RE: MOTOR OR GENERATOR??
Carpe Cubile
RE: MOTOR OR GENERATOR??
RE: MOTOR OR GENERATOR??
My dumb question.
If it is a motor,where do you find the 400 volts to power it in a Lorry (truck).Go with the Induction generator idea,makes a lot more sense.
GusD
RE: MOTOR OR GENERATOR??
Power is supplied by mechanical or hydraulic power take-off.
When the refrigeration system uses electric motors, such as in this case, the electric power is derived from a generator coupled to the auxiliary engine.
RE: MOTOR OR GENERATOR??
If the AC motor is electricaly connected to an AC invertor fed from the truck 24 battery system, and mechanically coupled to the truck engine or transmission in some way. Then the fridge compressors could be driven by DC Motors.
As the AC motor is 'overhauled by the truck engine, it's DC bus would rise and charge the battery, or load sharte with it.
Setting the frequency to voltage output of the invertor would be interesting, but stranger things have been done to drive air conditioners on railway rolling stock.
Also I have used AC Invertors coupled to Paper Unwinders to supply energy to a DC bus supplying an AC motor Rewinding the same paper sheet. The Unwind acts as a brake to tension the paper and provides the majority of the energy the Rewind needs to tow the papewr of the Unwind. The rest being supplied by the mains via the common DC Bus. This saves heat lost by disc brakes used to act as a drag on the Unwind thus saving energy. Same principle different application.
RE: MOTOR OR GENERATOR??
Any induciton motor can be converted to a generator without any mechanical changes.
There are two or more methods:
One you drive a motor above its rated RPM plus the Slip % of it, then you apply power to one/three phase(s).
The motor will produce the energy into the biasing power.
So this case needs to an electric energy source to produce power.
The second method is simpler and is the use of biasing capacitors across the windings.
Again mechanical power is applied at RPM p;us the slip % of the motor.
The motor metal has a remnant magnetism that the capacitor in parallel with the inductance of the winding starts to resonate at the operating Frequency and grows fast until a full power voltage level is obtained.
There is a need of a ELC ( Electronic Level Controller) which is a voltage detector that inserts/remove resistive loads to maintain the desired output voltage.
There is an industry of small Hydro electric power plants that use induction motor as generators for a few KWs of energy at low cost.
I have used, Ceiling Fans as generators and induction motors for 40 watts to 15 KW hydro-electric plants.
Other methods are a bit more complicated, no comment at this time.
Regards
Nando
RE: MOTOR OR GENERATOR??
Thanks,
RE: MOTOR OR GENERATOR??
RE: MOTOR OR GENERATOR??
RE: MOTOR OR GENERATOR??
A customer brought in a motor for repair. It is a 3 phase motor 2 pole 400 volts off a refrigeration unit of a lorry. The customer says it is a generator.
///What does a nameplate say or read?\\\
The motor has a rotor and is connected star on the terminal block.When i power the motor it runs at the rated speed.So why does the customer say that it is a generator which is run by an engine???
///Please, would you post the nameplate data?\\\
RE: MOTOR OR GENERATOR??
Most all induction motors may be operated as generators.
The alternative Energy industry ( small hidro electric plants ) mayuse the indution motors as generator.
For a single phase you drive the motor above its rpm+slip and connect running capacitors to the phase winidng, the power available is about 80 % of the rated power as a motor.
For the 3 phase you may use it as a 3 phase power out or one phase out.
In both cases you connect capacitors to two of the phases with the ratio of C and 2C.
The value of the capacitance depends on the HP and the input voltage.
Also you may apply AC voltae to one winding and if you app;y RPM+Slip the motor is converted into a generator and feeds power into the grid, way to couple several sources of power to a single grid system.
I hope this helped
Nando
RE: MOTOR OR GENERATOR??
Just my $0.02..
Anyone know the procedure for flashing the field of a single phase generator....??
damengr
RE: MOTOR OR GENERATOR??
Last time I flashed the fields in a generator I used a 12 volt battery.Actually I had the wrong polarity,it was backwards ,so we reversed the leads and did it again.Eureka,we had power.
It was a few years ago and I don't really remember the
small detail, but for all its worth,if you use a battery
and just touch the field it should work.
Check your field resistance top make sure you don't have excess fire works.This is a momentary contact with the field leads.Somebody might have a more formalized procedure and thatwould be best.Probably wouldn't differ much from what I mention,but just to be sure.
Good luck
GusD