12
DC Motors
Operation
Balance
Motors are dynamically balanced to commercial limits unless ordered
differently. Balance is done with a full length 1/2 height shaft key. A full
shaft key is shipped with the motor. Sheave or coupling should be balanced
with a 1/2 height shaft key.
Table G Standard Dynamic Balance Limits
Series Wound Motors
Important:
Series wound motors must be solidly connected to the driven
machine and never operated without load to avoid possible
destructive high speeds.
Motor Start-up
Highest Rated Speed
(RPM)
Maximum Amplitude
(Inches)
3,000 - 4,000
0.0010
1,500 - 2,999
0.0015
1,000 - 1,499
0.0020
Up to 999
0.0025
!
ATTENTION:
To guard against personal injury and/or machine
damage, observe the following precautions before initial start-up:
•
Remove all unused shaft keys and loose rotating parts to
prevent them from flying off. Replace covers and protective
devices.
•
Verify that all separately excited fields are excited at their rated
voltage and that relative polarities of all fields are correct. See
“Checking Relative Polarity of DC Motor Fields” on page 14
•
When the motor is supplied as part of drive system, refer to the
Drive User Manual for operating instructions. Tachometer
feedback must be properly connected for closed loop
operation. Reverse polarities or broken connections can cause
dangerous overspeeds.
Maximum safe mechanical operating speeds are shown in
. Motor control circuitry must prevent motor
speeds from exceeding the stated values.
