Rotary Design

Industry: Power Supply Mfg.
Problem: 50hz.Test @1500KVA over a voltage range of 323 to477V.

The internationally recognized manufacturer of an innovative and revolutionary high tech electromechanical replacement for DC battery banks used in large Uninterruptible Power Systems sold in conjunction with and by Cat Standby Diesel Engine Dealers needed a 1500KVA, 1200KW source to test his units at 50hz over a range of 380V.+/-15%(323V.) to 415V+/-15%(477V) for overseas sales.

Solution: 1500SYN6050

Solution: The above 1500KVA unit features a synchronous motor at 1800RPM coupled to a synchronous generator at 1500RPM thru a gearbox and equipped with a 300hp pony motor directly coupled to the synchronous motor thru a shaft extension. This design incorporates several advantages:

1. The use of the pony motor results in "no surge" starting--that is, the unit never draws more current from the utility than it would need when operating with a full load on the generator--even when starting the 1875hp synchronous motor. In contrast, a wye-delta starter would result in a 300% surge and that's guaranteed to dim anybody's, if not everybody's, lights.
2. Starting Surge of 480V, 3ph., 60hz. Induction Pony Motor--1685A.
   Total amperage reading on utility line when 1875 hp. Motor comes on line--260A.
   Total amperage on utility line when full 1500KVA 50hz load is on generator --1847A @480V., 60hz.
   Starting Surge of a normal wye-delta start 1875 hp Synch.Motor---5241A.
3. The synchronous motor is equipped with a VAR/Power Factor Controller which allows the operator to operate at 1.0 power factor automatically at all times regardless of changing loads which means that the operating cost of this test set is minimized at all times automatically with no operator attention required. Even better, the unit can be adjusted to act as a synchronous condenser, that is it can, in effect, feed back reactive power into the building load and reduce the power factor bringing the KVA(apparent power) closer to the KW(real usable power) of the entire site. Some customers actually buy and run synchronous motors on line with no load in place of capacitor banks for power factor improvement. Of course, the higher the test load on the generator, the less reactive power that can be fed back to the utility.
4. This unit is equipped with our digital output meter with an RS485 output and software for test recording. When the unit is started, a pushbutton results in a base printout of all parameters that is time dated. At each load change, a timed printout can be generated showing the various readings at that load and the length of time involved to the next change etc.
5. The unit is equipped with a PMG to provide "clean"(not affected by the distortion fed back into the supply line by the test load) operating power to the voltage regulator.