# Unknown motor, specifications interpretation and use

I got a motor on the picture. Does anyone know what it was used for? My main question is if is it feasible to use it as a barbecue motor or is it too strong? Can I connect it to one or three phases only? I would like someone to explain specifications of motor with easy to imagine answer so that we, that don't know anything about that stuff, can benefit from it.. :)

If specification plates aren't clear enough I can retype them... Please let me know if this is the issue.

[UPDATE]

Current wiring scheme:

Cable from the black thing above (connected with the red and black wire) goes to the back side of the motor as seen there:

• I don't know what exactly you need the motor for, but seems a bit overkill for a barbecue...unless you are trying to beat some guinness :) Awesome pictures anyway! Apr 20, 2012 at 11:23
• Looking at the input voltages, I'd say that it probably can be set to work both in single phase and tri-phase mode. Apr 20, 2012 at 11:25
• @clabacchio In these parts, it's not uncommon to put a whole pig on a barbecue and I guess that some force would be required to keep it rotating. Unfortunately, I don't know what are the specifications of commonly used motors, so I can't say if this one is overkill or not. Apr 20, 2012 at 11:27
• @PrimosK Do you have a multimeter? If yes, can you tell us the resistances between the screw terminals? Apr 20, 2012 at 11:30
• Finally someone that knows how to use a camera! Apr 20, 2012 at 12:43

Your motor is 750 Watt and can be wired to work on 220v and 380V.
It is likely that the wiring diagram for the motor shown below is applicable to your motor. This is a lower rated wattage unit.

The gearbox output is 40.5 RPM - about 1.5 seconds per rev.

Torque reading appears to be 145 Nm = 145 Newton metre or about 14.5 kg.m

Sanity check: Watts = RPM x torque in kg.m.
So torque in kg.m = Watts/RPM
= 750/40.5 = 18.5 kg.m =~ 182 Nm = about right.

14.5 kg.m will exert a "force" of 14.5 kg at a radius of 1 metre or 29 kg at 500 mm radius. That is very very ample for rotating a balanced BBQ pig of any sensible size.

It is not too strong per se but will tear your arm off if you insist if you allow it to exert force at small radius.
Say 15 kg at 1 metre, 150 kg at 100 mm. 750 kg at 20mm radius. Do not try and arm wrestle with it!!!

The material below found here appears to relate to a Koncar motor of about half the current rating.

Connection as shown is for 220V (I think) with alternative for 380 V (2 phase I think) shown on the connection plate. Testing resistance between the two input leads when in each arrangement should give a guide as to which is which - or if you can read Yugoslav.

1. PODACI NATPISNE PLOČICE

Cilj vježbe:
Identifikacija vrste stroja i njegovih nazivnih podataka

a) S natpisne pločice ispitivanog stroja očitati potrebne podatke stroja: Un, In, Pn, nn, fn, cos Phi_n, proizvođač, tip, serijski broj stroja (ili inventarski broj).
b) Odrediti vrstu stroja i vrstu namota stroja.

1.3. Pitanja za pripremu vježbe:
Nužno je poznavanje osnovnih podataka natpisne pločice ispitivanog transformatora

a) Koje najvažnije fizikalne veličine treba sadržavati natpisna pločica transformatora ?
b) Kada se mijenjaju podaci natpisne pločice i zašto?
c) Koje namote može imati asinkroni motor, kakvi namoti mogu biti i koji su osnovni načini spajanja namota ?

1.4. Literatura:
a) predavanje
b) Wolf R.: Ispitivanje električnih strojeva I; skripta
c) Nürnberg W.: Ispitivanje električnih strojeva.
d) Avčin, Jereb: Ispitivanje električnih strojeva

Another refence document of probably some degree of relevance
Koncar 3 phase induction motors. Various versions of the %Az and 80B - none seem to exactly match yours at a glance but one may. Mainly rating information.

• I don't understand a word :) But it seems that this motor is a 220W instead of 750 Apr 20, 2012 at 12:24
• Hehehe.. I understand it... It didn't answer my question but anyway great resource... Can you provide a link to this document please... Apr 20, 2012 at 12:27
• @PrimosK according to this data, you can spin a row of some pigs with this :) Still looking forward for the barbecue (I just have to cross the sea) Apr 20, 2012 at 15:39
• You're welcome.. :) Maybe I should organize one Stack Overflow meetup picnic.. :) Apr 20, 2012 at 15:47
• Regarding the answer it would be better to delete the part that is in Croatian/Serbian language because it is nothing concrete in it... Those are more something like exercises without solutions... Apr 21, 2012 at 9:32

It's a 3-phase 4-pole induction motor: synchronous speeds for 50Hz are 3000RPM, 1500RPM, 1000RPM, 750RPM and other divisors of 3000, whereas the nameplate on the motor shows 1350RPM which is just below synchronous speed for 2 pole pairs.

(3-phase judging from Russell's post -- I can't tell from your pictures/diagrams)

I don't believe you can start a 3-phase induction motor from single-phase AC power, and if you run from single-phase I'm not sure it will do that well; there are gadgets that allow you to do so by generating a 3rd phase (a friend of mine has one for a milling machine -- it's a little motor-generator that creates a 3rd phase to complement the 2 lines on single-phase power) but for <1kW motors it's probably not worth it to go that route.

Probably the easiest way to run from single phase is to hook up 2 of the 3 phases and use a capacitor between one of those and the 3rd phase, but I couldn't tell you off-hand how to pick a capacitor that would work well. (See this page for more info, though.)