Bypass not in range; either frequency or voltage

Anonymous user · ‎2021-06-30

We installed a new SRT6KXLT last year and have received a few of these errors... maybe one a month. The unit has a step-down transformer. I have read several posts regarding the Input voltage and Output voltage. Our Input is 220. The Output selected on the UPS is 240. There is only an option for 208 and 240. Is leaving the Input at 220 going to cause any issues or do I need to have the Input changed to 240? I would rather not have to do this. Looking for advice and reasons why I would need to.

Current Status - Input - 221.1; Output - 239.6.

Malvineous_apc · ‎2021-06-30

Bypass is used when the UPS has a fault and can't run off the battery. Normally if there is a fault (say the batteries are old and don't hold a charge) the UPS will switch to bypass mode where it simply feeds the input mains AC to the output.

However the UPS still monitors the AC input and if it goes out of range (e.g. the voltage is too high or low) then it won't switch into bypass because it doesn't want to pass that bad voltage through to your connected devices. So the warning basically means the power quality is not good enough, and should the UPS fail and have to go into bypass, it won't - and instead it will just shut off and everything will lose power.

It's nothing to worry about as normally the UPS won't be going to bypass mode.

Having your output voltage set as high as possible provides some benefits (lower current, increased efficiency) so there is no problem having it set higher than the input.

Perhaps check what voltages you have configured as your high and low cutoffs, and adjust these if necessary. For example if you have told the UPS that the minimum voltage you will accept is 215 V but your power occasionally drops to 210 V, then telling it you will accept passing down to 208 V through to your load will stop the bypass warnings. Looking at the logs when these messages arrive should tell you what the voltages were at that time so you can make the decision whether that voltage is acceptable or not.

See Answer In Context

Malvineous_apc · ‎2021-06-30

Bypass is used when the UPS has a fault and can't run off the battery. Normally if there is a fault (say the batteries are old and don't hold a charge) the UPS will switch to bypass mode where it simply feeds the input mains AC to the output.

However the UPS still monitors the AC input and if it goes out of range (e.g. the voltage is too high or low) then it won't switch into bypass because it doesn't want to pass that bad voltage through to your connected devices. So the warning basically means the power quality is not good enough, and should the UPS fail and have to go into bypass, it won't - and instead it will just shut off and everything will lose power.

It's nothing to worry about as normally the UPS won't be going to bypass mode.

Having your output voltage set as high as possible provides some benefits (lower current, increased efficiency) so there is no problem having it set higher than the input.

Perhaps check what voltages you have configured as your high and low cutoffs, and adjust these if necessary. For example if you have told the UPS that the minimum voltage you will accept is 215 V but your power occasionally drops to 210 V, then telling it you will accept passing down to 208 V through to your load will stop the bypass warnings. Looking at the logs when these messages arrive should tell you what the voltages were at that time so you can make the decision whether that voltage is acceptable or not.