Power Supply to PLC System Using Genset

[zai_jnr]

Dear All,

Currently I'm working for PICO Hydro system that installed at remote rural area which there have no power supply from service provider.

The PLC system should be using UPS Battery system to power up the system.
Due to UPS Battery still not available and we decide to use Genset to power up the PLC system for looping check, manual operation and etc.

Is it possible to use direct Genset to power up PLC System and another electronics module such as DPM, Power Regulator etc.

I'm just wondering and worry if there have any power distortion from Genset when power up the PLC system. And will effect our Electronics Module and PLC Controller.

Any advice Sirs?

 

[BobB]

If the generator is a Cat, Cummins or Kohler you should be OK I think. I would be pretty suss about a cheap Chinese generator though.

 

[BryanG]

It depends on the Genset. Smaller gensets tend to come in two versions, the better ones use an inverter to create the AC voltage rather than taking directly off a generator. These are sold as suitable for use with electronic devices, but only come in smaller sizes, typically up to 3.5kW. Our machines are supplied by standard onboard diesel generators 60KVA, we did have a problem with a few power supplies that died, they were Siemens ones and rated to 270V a.c. , we changed to a MeanWell wide voltage range supply that can go from 180V to 550V and haven't had a failure in about 5 years. Standard gensets have an AVR (Automatic Voltage Regulator) to keep the voltage to setting, however they often only work on one phase, so we always make sure that the electronics are supplied from the phase that the AVR monitors. As always make sure that everything is well earthed and avoid earth loops. And not wishing to court controversy again, but make sure you earth the output of an DC power supplies. Isolated DC supplies aren't about isolation, they are about being certain that 230Va.c. never reaches 24V d.c. circuits.




(Just noticed that it was BobB that answered originally, not try to cause trouble over my DC grounding comment )

 

[arpus4KM]

I would verify all the power you plan to use. I can tell you from experience that I showed up to help troubleshoot why a Transfer Switch wasn't completely running through it's program on a Micrologix 1100. It was a CAT generator and the PLC power was through both the building and generator. When the Generator kicked on the PLC power would jump from 24v to 32v and cause a Brown-out condition. This caused the PLC to power cycle due to the higher voltage.

I only found it because I Was using my meter to look for a power loss. and I cycled through the min/max, I figured we lost power to it for a split second, but it turned out that the alternator/trickle charger/charging system (whichever part generated the 24v for the generator, the Generator tech was in the Generator building while I was at the controls area) was causing the problem. When this happened it wouldn't complete it's transfer from building power to generator power obviously and put the generator back in an idle state.



So.... I think the answer depends on which plc, which generator, and how clean the power is along with whatever other factors others know about.