Current Pulldown Limit
The Pulldown Demand Limit Setpoint timer is in effect and the Compressor Motor current is
greater than or equal to the Pulldown Demand Current Limit Setpoint value. The Pre-rotation Vane
operation is being inhibited as described in Motor – High Current Limit message below.
Motor – High Current Limit
The Compressor Motor current is greater than or equal to the local or remote Current Limit
Setpoint. The Current Limit Setpoint is programmed over a range of 30 to 100% of the Chiller Full
Load Amps (FLA). When the motor current increases to the Inhibit Open threshold, the Pre-rotation
Vanes are inhibited from further opening. This prevents a further current rise. If the current
continues to rise to the Start Close threshold, the Vanes begin closing until the current falls to the
Stop Close threshold. Automatic Vane operation is resumed and this message automatically clears
when the motor current decreases to the Allow Open threshold.
The thresholds are different for the various motor starter applications. To allow field calibration of
the CM-2 Current Module, pressing the Pre-rotation Vanes OPEN key in SERVICE access level, starts
a 10 minute timer during which the current limit thresholds are elevated. See the following table.
Table 174: Motor Current
Motor current (%FLA)
Vane control
Electro- mechanical/Solid State Starter
VSD
Service mode
On rise, inhibit open
100
100
107
On fall, allow open
98
98
106
On rise, start close
104
103
110
On fall, stop close
102
101
109
An example of current limit is as follows: If a Solid State Starter chiller FLA is 100 Amps, and the
Current Limit Setpoint is 50%, the following will occur:
•
Amps – inhibit vane open
•
Amps – vanes begin closing
•
Amps – vanes stop closing
•
Amps – allow automatic vane control
Load Control Mode
Access Level Required: SERVICE
The Compressor Motor Variable Speed Drive has not yet reached full speed after having been
commanded to do so in Manual Speed Control mode. While this is displayed, the Pre-rotation Vanes
are inhibited from further opening.
Start inhibit messages
Anti-Recycle XX min/Sec
The chiller is inhibited from starting because the 30 minute anti-recycle time has not yet elapsed.
Time remaining is displayed.
Vane Motor Switch Open
The chiller is inhibited from starting because the Pre-rotation Vanes are not fully closed.
Motor – Current >15% FLA
This start inhibit is instantaneously set whenever the chiller is not running and a motor current
of greater than 15% FLA is detected. The oil pump is started as soon as this fault is detected. The
167
Model YK Style H Centrifugal Liquid Chillers with OptiView Control Center
