If we have a large MV motor fixed speed with forced lubricated sleeve bearings and the motor manufature is offering insulated bearings DE & NDE ( with DE earth cable )Does the oil inlet & outlet pipework which has ANSI / DIN flanges, do these flanges have to be insulated. And if so how are are...
Regarding Siemens HV motors does anyone know the meaning of of "Torque class KL4 KL5, KL16", which have appeared on some data torque curves. Do you think this could mean type of rotor construction, double cage etc
With a Zone 2 motor where we have several accessories, for example Exe stator and Exe bearing RTD's wired to a EExe II auxiliary terminal box as standard, would it be possible to have the RTd's wired to a Exd auxiliary box
Looking at a 6 Mw 11 Kv synchronous machine efffy 97% PF to be 0.9 leading to 0.9 lagging for continous operation,and require a 33kV / 11 kV power transformer. KVA rating of transformer, would this be based on KVA rating of motor
Air to air cooled motor with air heat exchanger whereas the cooler tubes are manufactured from a Aluminium alloy AI MgSi would this materiall be suitable for offshore use
Hi Guys.
Just trying to understand soft starter principles. If we want to soft start a 3Mw motor 6Kv with 60% starting torque, and 650% current, compressor drive.and we limit the starting current to 400%, what happens to the voltage, how do we calculate the corresponding voltage at this point...
Hi guys can anyone please give a estimation or rule of thumb for determining the heat loss fron a water cooled motor ( Heat Exchanger )For example we hae a 1Mw 4p motor with efficiency at FL of 95.8%, Water inlet is 33 Deg C , and oulet approx 39 Deg C, Water flow rate is 9.4 m3/h
We have a 9MW 4P 6.6Kv 60hZ Synchronous Motor, and we are thinking of using this on another plant where the frequency is 50 hZ. We know we will have to rate the motor for a lower power, but is this feasable. What are the issues we have to think about
Customer has a 5MVA Generator operating in island mode, and the question is what would be the biggest motor we could connect to this GEN considering a typical IEC 6Kv motor with starting current ratio of 6.5 times flc.Efficiency 95% and power factor 0.90, and a starting voltage of 80%
Calculating volt drop at say 6Kv bus, with 126MVA, and a motor rating of 7.7Mw 6Kv FLC 832A and starting current of 4401 a ( Is/In 5,29) and volt drop on 6kV net not to exceed 15% then on DOL we get 27% drop.
So if we introduce a auto transformer with a rating of 9MVA, impedance of 6% and say...
From the point of view of electric motors whereas UL are moving to harmonizing the US zone requirements etc.Are class 1 division 1, and class 1 division 2 still applicable, or is now the correct thing to do to offer class 1 zone 1 or class i zone as the case maybe. Or are the two concepts...
Can one of you kind gents help me out here. We have specification from a client stating "" that the vibration of the motor shall not exceed 0.5 mil double amplitude in any direction at full or no load "". The motor in question is a IEC 400 frame with sleeve bearings. The motor spec states...
Have question regarding Zone 2 EExnA motors according to
IEC. We have noticed we have an offer for a 3.3Kv motor, which as a Exe terminal box. ( i.e the terminals are according to IEC regarding clearances etc ). However this terminal box is also equipped with a pressure relief diaphragm. I...
Is it possible to assess the heat loss from a 6Mw 4p 6kv motor with an efficiency of 97% (FL) and assumming the secondary cooling circuit is routed away ( air or water ), what heat would be rejected into the room.
Not being mechanically minded why does API 541 Standard ( 4th Edition ) state for certian machines a heat treated forged steel shafts is required ( clause 2.4.5.1.3 ) as opposed to hot rolled shafts. What is the benefit of using a forged shaft. European manufactures appear to be hot rolled as...
Is their a motor frame dimensional charts for NEMA Motors above 355 frames, for a given HP / Speed relationship, where we could compare the difference between an IEC and NEMA motor
Hi guys, for IEC motors when considering degrees of protection, it quite clearly defined under IEC60034-5, Degree of protection using IP codes. Is there anything in NEMA standards which is equilavent to. We have come across a list of NEMA enclosure types from 1 to 12, for example NEMA 4 or NEMA...
Have you guys come across a system whereas large MV motors equipped with self contained oil lubricated sleeve bearings, are modified or supplied with purging pipes in the bearing housing so the end user can purge the air above the oil to remove any contaniments like sand or dust.The purging...
