UPS Loads That Cause Problems
Q: What UPS inverter loads have the potential to cause problems with UPS operation?
A: The following load types either have very high inrush currents on startup or draw far more power than equivalent-sized loads:
- Laser printers
- Air conditioners and pumps
- LED lighting (leading power factor)
- Blade servers
- Motor loads
Connecting these to a UPS causes it to go to bypass continuously with constant alarms, and during a battery discharge they will affect inverter operation. The two ways to handle them:
- Leave them off the UPS entirely (preferred for air conditioners and motors — see FAQ - Air Conditioner on UPS)
- Calculate the peak instantaneous power draw on startup and include this in UPS sizing — peak is often not on the device rating plate and must be obtained from the manufacturer
Connections
- FAQ - Air Conditioner on UPS — relates, source: https://standbysystems.co.za/ups-batteries-questions-and-answers/
- FAQ - How to Size a UPS — relates, source: https://standbysystems.co.za/ups-batteries-questions-and-answers/