Starting; Direction Of Rotation; Starting Of Machines With Slip Rings; Starting Of Ex P Machines - ABB AMA Series Manual

Manual for Induction Motors and Generators

5.6.3 Starting

5.6.3.1 Direction of rotation

***Following chapter for rotor type: Slip rings

5.6.3.2 Starting of machines with slip rings

***Following chapter for protection type: Ex p

5.6.3.3 Starting of Ex p machines

48 - Commissioning and Start-up
The first start should last only about one (1) second, during which the direction of rotation of the
machine is verified. The direction of rotation of possible external blower motors must also be
verified. It is also verified that the rotating parts do not touch any stationary parts.
NOTE: If the machine does not have an axially locating bearing, and the machine is started
uncoupled, it is normal that the shaft will move axially before stabilizing.
The objective of the first starting is to check the direction of rotation of the machine. The
machine should turn in the same direction as is shown with an arrow located on the frame or the
fan cover. The direction of rotation of the external blower motor is indicated by an arrow near
the blower motor. The machine may only be operated in the specified direction of rotation. The
direction of rotation is indicated on the marking plate, see Appendix Typical position of plates.
Machines suitable for reversing operation are labelled with a double-headed arrow on the rating
plate, as well as on the frame.
If the desired direction of rotation for some reason is different from the one specified on the
machine, the cooling fans, in inner and/or outer cooling circuit, must be changed, as well as the
stamp on the rating plate.
To alter the direction of rotation, interchange the power supply phases.
Machines with slip rings cannot be operated without a starter. The starter is typically a variable
resistance connected to each rotor phase via the slip rings. The selection of the starter is done
according to required starting torque and current. Starting is typically done with nominal current
and nominal torque.
During starting the starter resistance is decreased and speed for breakdown torque is shifted
towards higher speed. The speed of the machine is always between actual breakdown torque
speed and synchronous speed. Operation between standstill and breakdown torque, or stalling
during starting, is not allowed.
NOTE: Failure in starting the machine without checking the adjustments of the complete slip
ring gear can result in serious damage! The connections to the starter and its functions
shall also be verified.
NOTE: The brush-lifting device must be in starting position before starting the machine.
The Ex p machine enclosure is explosion protected during operation by pressurizing. Before
pressurizing, the machine enclosure shall be purged with clean air. Detailed commissioning
instructions for the purge and pressurization equipment are given in a separate manual. In case
3BFP 000 050 R0101 REV E