b) With UPS Supply:
Assuming the evacuation speed to limited to 1/4
th
of nominal motor speed; a rule of thumb is to
use a UPS with power rating of at least half the motor power. For example: A 5 kW UPS may be
used for a 10 kW motor.
In reality, the exact power requirement of the UPS is dependent on many factors including shaft
efficiency, evacuation speed and motor plate values. The best way to determine the exact
requirements is to find it empirically. While measuring the power requirements, the following
procedure may be used:
- Instead of a UPS, mains power is supplied to the real system
- Car is unloaded
- Evacuation speed limit is set by the “12.3-BAT.Speed” parameter (recommended to set it to
1/4
th
of nominal speed)
- The current drawn from mains during evacuation in downwards direction is measured.
Minimum required power (W) = 220 V x Measured current (A)
Minimum required power (VA) = 220 V x Measured current (A) x 1.4
The UPS should be chosen such that its power rating is at least 1.3 times the calculated minimum
power requirement.
The power that will be drawn from the UPS must be limited by “12.4-UPS POWER” parameter. If
power is not limited, the UPS may be overloaded.
If the UPS will also power other electrical loads during evacuation (i.e: control panel, mechanical
brakes, door operator, etc), the power required by those loads must also be considered on
calculation of the UPS power.
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