Hi all
On a hydro power generation project under construction we have two generators connecting to the power system by a single three winding transformer. The step up transformer consists of three single phase units each with two 13.8kV secondary windings. Our expectation is that the overall...
Hello all,
Do you have any experience of running low speed (365rpm, 16 pole) motors with low power factor (0.56 @ 100% load, to 0.38 @ 50% load) on a VSD. In this instance the motor is 25kW with rated current of 80Amp. The VSD has been sized to the motor rated current not the motor kW, hence...
I have situation of when a 280kVA standby generator is supplying the site load (mains fail) the voltage oscillates by approximately 5V at around 2Hz. The site load is about 135kW @ 0.98 leading, and consists of a UPS, air conditioning plant (VSD driven) and the usual basic building load. The...
I have recently installed a GE Multilin 489 generator protection relay onto a 4MVA 11kV 4pole synchronous generator, with brushless excitation. The star point of the generator is conected to earth via the primary of a 100:1 11/root3 transformer. The secondary of the transformer is connected...
I've got a 500kW, 6.6kV slip ring induction motor, which uses a liquid starter to bring it up to speed and is then switched to synchronous operation. The starter has movable plates rather than relieing on heating to change the resistance. When starting the motor the operator monitors the...
I am installing new VSD's and motors on a crane that was originally built in 1965. I have been able to estimate that under the worst case conditions the current THD will be approximatly 35% (which will be virtually un noticable to the rest of the plant). However we are retaining some of the...
