The mains has been restored but generator is still running – UPS System
After a power cut, if a generator continues to run after mains power is restored, it may be due to several reasons: 1) The AMF panel could still be in a cool down period (generally 5 minutes). 2) Mains power may not meet acceptable voltage limits, prompting the generator to stay active to ensure continued operation. 3) The AMF panel may require a reset to recognize that mains power has been restored. Monitoring the AMF panel for voltage and frequency can help determine these conditions.
This is something which we get asked a lot about.
So you鈥檝e had a power cut, so the generator turned automatically as designed. The mains power has been restored. Yet the generator is still running!
Possible causes:
- Check the AMF panel. It might be that the changeover panel has switched back over to mains and the generator is just running through its cool down period. This is a preset time and is generally around 5 minutes. Have a look at the A MF panel to see whether your load is powered by the generator or the mains.
- Mains power is still not yet within acceptable limits. After a power cut it is common for the mains to come back but not be quite within the acceptable range. For example you may have 230V on L1 but you could have 180V on L2 and 0V on L3. Most changeover panels monitor all 3 phases. Therefore clever enough to realise that the mains power is still not correct and will therefore continue to run on generator to keep your operations working. If your AMF panel has a display, you can check the voltages of all three phases on the mains as well as the frequency and this will highlight whether the mains is there or not.
- AMF Reset.聽Sometimes the changeover panel needs a reset for it to realise that the mains power has been restored. This doesn鈥檛 happen often but it can happen.
