Machine Protection And Adaptive - Trane CVGF-SVU02B-E4 Operation And Maintenance Manual

62
Machine Protection
and Adaptive
Machine Protection and
Adaptive Control
Momentary Power Loss (MPL)
Protection
Momentary power loss detects
the existence of a power loss to
the compressor motor and
responds by initiating the
disconnection of the compressor
motor from the power source.
Power interruptions of less than
30 line-cycles are defined as
momentary power losses. Tests
have shown that these short-
term power interruptions can be
damaging to the motor and
compressor if the chiller is
reconnected to the line while the
motor and line phases do not
match. The chiller will be shut
down when a MPL is detected
and will display a non-latching
diagnostic indicating the failure.
The oil pump will be run for the
post-lube time period when
power returns. The compressor
and compressor motor are
protected from damage from
large torques and inrush
currents resulting from
reconnecting the compressor
motor to the power source
following a momentary loss of
power.
MPLs greater than 2 or 3 cycles
are detected resulting in unit
shut down. Disconnection from
the line is initiated within 6 line-
cycles of the power loss. MPL
protection is active anytime the
compressor is in the running
mode. (The transition complete
input has been satisfied.)
Note: MPL is defaulted to
enabled however can be
disabled, if required using
TechView ™ .
CVGF-SVU02B-E4