YORK YMC2 — MBC - W13 POSITION

The panel shows MBC - W13 POSITION. Both manuals print the message in this exact form only, with no alternate wording, and list it among the YMC2's cycling shutdown messages.

Shaft displacement is out of position at the impeller-end radial bearing, on the W axis: the MBC has measured shaft displacement greater than the trip threshold from center in the orthogonal radial axis designated W at the impeller end radial magnetic bearing, during Levitation or Rotation mode. The control center manual sets that threshold at 75 µm — approximately half of the air gap space to the touchdown bearing; the other manual prints 100 micron — approximately 2/3 of the air gap space.

When the message trips, the MBC ESD Fault contacts open (the other manual calls them the MBC Fault contacts). The MBC remains in Levitation mode with the motor shaft levitated until it is commanded to de-levitate over serial comms or, per the control center manual, until VSD DC buss power depletes.

• Shaft displacement greater than 75 µm from center in the W axis at the impeller end radial magnetic bearing — the other manual prints the trip value as 100 micron.
• The excess displacement is measured during Levitation mode or during Rotation mode; either state can produce the message.

• Trip threshold: shaft displacement greater than 75 µm from center in the W axis (control center manual); the other manual prints 100 micron.
• Air-gap reference for the trip point: approximately half of the air gap space to the touchdown bearing (control center manual); approximately 2/3 of the air gap space (other manual).
• Release threshold: displacement less than 75 µm (control center manual); less than 100 micron (other manual).

Release is automatic; no separate reset step is described. The shutdown is released when displacement is less than 75 µm (control center manual) or less than 100 micron (other manual) — that is, once the measured W-axis displacement falls back below the trip threshold. Until then, the MBC stays in Levitation mode until commanded to de-levitate over serial comms or, per the control center manual, until VSD DC buss power depletes.