Blower Motor; Field Supply - BRUEL & KJAER System V Instruction Manual

4.2.2. Blower Motor
An AC Blower Motor drives the Head and Field Cooling Fan. Since the motor speeds up
to a max. of 2900 RPM when the mains frequency is increased (to 440 V, 60 Hz), in ­
creased cooling is provided when the Field Coil dissipation is increased .
4.2.3. Safety Circuit and Field Supply
The three-phase power supply for the field supply is fed to the rectifiers located on the
safety circuit board in the base of the Exciter Body . The sa fet y circuit provides the follow­
ing protective functions :
al Checks that all three phases are connected.
bl Checks that the cooling motor fuses mounted on the safety circuit board are intact.
el Checks that the phases are connected correctly to ensure against the cooling fan ro ­
tating backwards .
dl Checks field coil temperature with the help of a sensor in the field coils.
el Checks that the exciter head is mounted on the body.
Exci ter
~--
Side Support
~-------
/'.JIr---
Rotation Clamp Knob
Trunn ion Springs
Fig.4.3. Cross-section of the Exciter Support
Bearing/ Brake
High Frequency
Suspension
Engagem ent Knob
211057
29