Symmetra PX 30 kW 208V - In Forced Bypass

[Anonymous user]

We have a Symmetra PX 30 kW that has been sitting for about a year and a half due to building issues (old switch gear and asbestos concerns). We finally got the work done needed to connect our unit, and after fixing a phase issue, and locating the power modules that were in another building we finally fired everything up to get a UPS in Forced Bypass State message. I checked that the switch module wasn't in forced bypass, and we don't have an external bypass, and everything looks ok from that end. I try to put the UPS online, but it comes back with Cannot Perform Function on the display.

Is there anything I'm missing, or do I have a bad switch module? How do I test it?

Thanks,

John

[Anonymous user]

Thanks for the information. It turned out the jumper was on 13+14. I also noticed the ribbon cable connected to the board was loose, and re seated the connection. Everything looks good now and UPS is online.

[BillP]

hi john,

i asked one of our 3 phase power techs and here is what he said:

Besides the forced bypass switch (which you have already checked - thank you), the only other thing likely to keep a system in forced bypass is if the UPS thinks the Q3 breaker of a Maintenance Bypass Panel is closed.

The sensing for a Q3 breaker is located on the Maintenance Bypass Interface Board located behind the lower rear panel of the UPS. (Since this is behind a UPS panel, you should perform this work while the UPS is de-energized, with the DC breaker off, and have the system enable switch off). On the Maintenance Bypass Interface board, there is a row of 14 jumper blocks. A standard configuration would have jumpers in pins 5+6, and 13+14. 5+6 are a normally closed sensor for Q3 switch position, and 13+14 are to indicate the presence of switch gear. Since you have no external bypass, you would want to ensure there is a jumper in 5+6, and remove the jumper in 13+14.

Once the jumpers have been changed, re apply power (AC, DC, System Enable), and your forced bypass alarm will likely be cleared. You will then likely be able to command the UPS online.

If this does not solve your issue, or you have any questions along the way please call into our three phase support team 1-800-800-4272 opt 5, then opt 4.

Lastly, I strongly suggest you work towards getting a Maintenance Bypass Panel for this UPS. While your standard repairs to the UPS (replacing batteries and power modules) do not require external bypass, or completely turning the UPS off, some things do. For example, if this is a 40K UPS frame, the static switch is not a hot-swappable module, if it ever had to be replaced or serviced, you would likely need to schedule downtime for your UPS and the connected equipment.

[BillP · Accepted solution]

ok, great!