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Bypass settings of Single Phase Symmetra UPS systems

Issue:
What are the different bypass settings of a single phase Symmetra UPS?

Product Line:
Symmetra Power Array
Symmetra RM
Symmetra LX

Environment:
All serial ranges

Cause:
These Symmetra UPS systems are designed to operate off of a nominal input voltage of 208V or 240V. However, these UPS systems can operate in the on-line mode of operation over a wide input voltage range, 155-276V. When the input voltage is within this range the power modules are capable of producing a steady output voltage. When the input voltage exceeds either of these thresholds the UPS will operate in the on-battery mode of operation until the utility voltage is corrected.

When the UPS is overloaded, or there is a fault that prevents the Power Modules from powering the load normally, the UPS will consider powering the load via Bypass. The selectivity of this bypass operating range depends upon the Bypass setting of the PowerView display.

Resolution:
The Bypass setting can be accessed via the PowerView under the Settings menu. This setting will dictate how the UPS will react to UPS failure. Should the UPS encounter a failure where it can no longer support the equipment the UPS can react in 1 of 2 ways:


1) Go to bypass
2) Drop load

When the UPS is set to Go to Bypass the bypass operating range is -20% to +10% of the phase-phase output voltage. When the UPS is set to Drop Load the bypass operating range is -12% to +6% of the phase-phase output voltage.  No matter which setting is chosen, if the input voltage is outside of the specified range the UPS will turn off power to the load rather than subjecting it to undesirable voltage levels.

When commanded into bypass via the PowerView or an accessory only, is more selective. If the input AC voltage is outside the range -12% to +6% relative to the input voltage selector setting, or the output frequency is not synchronized to the input, the UPS will not allow itself to be commanded to bypass if it is currently operating on-line.  When commanding the UPS into bypass via an accessory, the bypass setting mentioned above is NOT used.

Keep in mind that, when absolutely necessary, the UPS can still be forced into maintenance bypass via the breaker on the UPS. If the UPS does not allow itself to be commanded into bypass via the PowerView or any other accessory, damage to connected sensitive loads may result by forcing bypass via the maintenance bypass switch.

 

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