Machine Protection

and Adaptive

Control

Momentary Power Loss (MPL) Protection.

Improved power measurement and protection algorithms allow the unit to accommodate more power anomalies than ever. If the chiller must shut down, faster restarts get the machine up and running as soon as possible.

Momentary power loss (MPL) 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.

MPL’s 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).

MPL is enabled however can be disabled, if required via the service tool.

Figure 29. Sequence of operation: momentary power loss, (DynaViewand starter module remain powered)

Enforce Stop to Start Timer

(5 to 200 Seconds 7 Sec is Default)

72

CDHF-SVU01C-EN

Page 72
Image 72
American Standard CH530 manual Machine Protection Adaptive Control, Momentary Power Loss MPL Protection