Operator`s manual
Powerware Plus 18 Operator'sManual(LTM-1336B)10
Bypass Plus (50/60-Hz inputs and outputs only)
The UPS Bypass Plus feature contains two features in one: Automatic Bypass and
Maintenance Bypass. The UPS Bypass Plus features are available only when the
Bypass Configuration switch is enabled; this switch is factoryĆconfigured according to
your order.
Bypass operation requires that input and output voltage and frequency are the same. If
the UPS is operating as a voltage and/or frequency converter, bypass must be
disabled. See Final Configuration" on page 47.
Automatic Bypass
The UPS automatically transfers the protected equipment directly to the utility AC
power, provided the bypass source is available, when one of the following conditions is
true:
Load current is between 106% to 124% of rating for 10 minutes, 125% to 149% for
30 seconds, or greater than 150% for 10 cycles.
UPS internal temperature exceeds safe operating range.
UPS output falls outside of the specified limits of voltage.
Output real power exceeds specified limits.
Load current inrush exceeds peak current capability (surge).
When the unit is in Normal mode and automatically transfers to Bypass mode due to an
overload condition, the UPS attempts to return to Normal mode. After output
realĆpower overload failure or any other abnormal condition, return to Normal mode
must be done manually (system startup). The UPS remains in Bypass mode if three
autoĆstart attempts fail within a 10Ćminute period.
Maintenance Bypass
The Maintenance Bypass switch is located under the top cover of the UPS (see
Figure 10 on page 39). When activated, this switch allows for onsite servicing of the
UPS. Be sure that the output breaker is turned on(I).
This equipment is always electrically live. Users must remove utility
power by external means.
Failure to follow instructions results in load power interruption.
When operating in Maintenance Bypass, your equipment is not protected
from power outages.
To transfer the load to Maintenance Bypass:
. Hold the UPS Off button until the Normal indicator goes off and the Bypass
indicator illuminates.
. Turn the Maintenance Bypass switch from off to on.
. Open (O) the input breaker and battery breaker.