Recent content by TommyOO7

Milovan, I would rather concentrate on Circuit Breaker trip settings. Your synchronous motor (SM) already has asynchronous motor (AM) inside it, much larger size then you are considering for your pony motor. SM can not start on its own, it must be brought to near nominal speed by other means...

I would say that good electronic motor protection relay is enough. Basically when this happens the motor is in short circuit mode and (well tuned) motor starter should open the circuit before any damage to the motor. Check GE Multilin and Switzer ... TommyOO7

Try this NFPA 70E Standard for Electrical Safety In the Workplace

This is what I would do: 1. Check the motor direction of rotation, ie. motors are helping each other not fighting each other. I guess you did this and is out of question. 2. When you select SCIM, you should carefully match the torque curves of a new motor and the old (WRIM) one. Breakdown...

Barrie66, As you said the job is ME (Middle East), why do you need manufacturer in N.A.? Why don't you ask your local representatives of ABB, Schneider, Siemens, ... to give you the price for installation in ME! They all have both IEC and NEC equipment! Tommy

Did you try this and know the answer (and just testing us) or not?

usamaegypt, everything is possible, it's just a matter of time and money. Why don't you just ask a few of the biggest motor players to give you quotations for both options. Then discuss with them maintenance and operational cost and compare with energy savings on 22kV. How does this sound to...

It seems that you switched the terminals of one phase (T3-T6). Am I right? Tommy

What's the application for the motor? Size?

jraef, I didn't know that, in the IEC world, there is a 3-ph, 240V power supply (distribution voltage)! I thought that min. 3-ph, voltage is 380V (or 400V, 415V). 220V (230V or 240V) is 1-phase (Line to neutral) voltage! So, my question is why would anybody make a motor for the voltage which is...

That energy is not lost, that's a problem for electronic converter. Properly designed capacitor can accumulate that energy and send it back in next cycle (or something similar). But for the speed you are talking about, I don't see any other rotor construction which could be used. I wander what...

But, all motors are designed to run in Delta connection. So if it is connected in Y, everything is fine, just lower phase voltage and phase current. Motor windings' insulation level is based on the line voltage, regardless of the connection. Correct?

Tell me then how Y-Delta motor starting works! Two different voltages are used or the same voltage? It is the same (line) voltage, but different phase voltage and each motor is designed to run permanently in either connection!

Basically in Method F, Stray Losses are measured, and in Method F1 are calculated or assumed! Is that correct?

Did you consider Switched Reluctance Motors (SRM)? They are made for extremly high speeds (> 20,000rpm ). Rotor is made of laminated steel only, no windings, no magnets, nothing, just steel. They have very simple mechanical construction, but must have electronic controller (kind of VSD). Check...