UPS SYSTEM STATIC AND MECHANICAL BYPASS

[dydt]

We have a 60kva Merlin Gerin UPS for data center when one of its module broke down (draw-out type). When it faulted out it shifted to the utility line via static switches. I am aware that the load side,the line side and the inverter are "sync". Anyway using the manufacturers instruction, there is a mechanical bypass which we can also use for maintenance. In short from static switch we shifted to mechanical bypass and changed the defective module. Then from mechanical to static and back to the inverter and the UPS is back in service. My question is, I am a bit puzzled with the mechanical bypass ( sets of breakers ). Will there be an arcing on the breakers that will affect the critical load when we switched to the static and vice versa. I know the repair is successful but this is something that bothers me technically. The computers were okay during the repair process..

any info. is appreciated..

 

Although you have not described the mechanical bypass (maintenance bypass) switch, it is common for these to be configured as "make before break". As a result, there is no "open circuit" time. Also as a result there should be no arcing.

The obvious presumption is that the maintenance by pass is used with both sources in synch.

 

[MDom]

dydt,MGE advises to follow the sequence of turn on the CBs ( I refer to user manual GALAXY PW E-51028230XT/DC,article
" system start up&quot :
close Mains 1 input switch Q1,the system powers up
the rectifier/charger automatically starts,then close:
1/ QF1- battery is on
2/ Q5N - load is connected to the invertor's output
3/ QS4 - static switch is connected to the circuit
and only now you can open Q3BP and then press the "inverter on" button on the control panel.
This sequence ensures the "make before break" principle.

 

[sanvapat]

I agree with MAIHAM, we have the same system, but from GUTOR,switzerland..Mechanical switch you are talking about is "Make before Break" switch.While operating mechanical switch, both lines ( from static bypass and direct) are in sync (on utility),so no question of sparking...

 

[sparky1976]

Dydt,
I agree with Maiham and sanvapat the manual by pass switch is made-before-break or zero break switch. It is the same with my system also made by solidstate.