Service Manual 32 – Contour 3 Series, Profiler & Advance – Approved Issue 5 Printed 2/13/2014 11:50:17 AM
54
Cooler Operation:
(cont.)
Fan Operation:
(cont.)
DC Brake
Whenever the fan motor is required to operate, the N-E5 uses the motor speed
sensor to checks if the motor is rotating.
This rotation of the fan and motor, may be due to air up draught in the dropper duct,
whilst the unit was not running.
The N-E5 will apply a brake to stop the rotation by energising the motor with DC
Voltage. This is to ensure the fan motor will not be energised and driven in the
reverse direction.
DC power will only be applied to the motor, if at the time the fan motor is powered,
the
motor
has not been previously powered for at least 10 seconds
, and that
rotation is detected above the minimum RPM
requiring the brake.
The DC brake will then remain ON until the motor speed sensor registers the fan
motor has slowed to a RPM not requiring the brake, before powering the motor for a
normal start.
The rate that the DC brake is applied, is a factory setting, and cannot be field
modified.
If the fan is operating in FAN_LIMP mode, then the DC brake will not be applied.
Allow for the 4 minute delay period to register the error on the Networker, before the
DC brake is disabled.