Poweramp VS VERTICAL SPECIALTY 4.2009 - Manual (Page 30)

TROUBLESHOOTING
Three-phase units only:
Platform does not rise.
Motor hums, but does
not run. No voltage is present on
one line.
NOTE: A motor that is
missing voltage on one line
is said to be single-phased.
Check for blown fuses at branch circuit disconnect.
Replace fuse. Determine cause of blown fuse.
Check motor starter as follows:
1. Disconnect wires at load side of starter.
2. Energize the starter.
3. Measure line-to-line voltage at line side of starter.
4. Measure line-to-line voltage at load side of
starter.
5. Line-side and load-side voltages should be
approximately the same. Replace starter if
voltage values are considerably different from
one another.
Check all wiring to motor for high resistance or no
connection.
Three-phase units only:
Platform does not rise.
Motor runs in reverse Phase reversed. Reverse any two legs at the branch circuit
disconnect.
Single-phase units only:
Platform does not rise.
Motor energizes, but
does not run. Line voltage too low. Check wiring to motor for high resistance. Check for
loose or corroded connections. Check if gauge of
wires to motor are of correct size and specification
for load requirement. Replace if necessary.
Defective motor centrifugal
switch. Replace motor.
Defective motor capacitor. Replace motor.
Symptom Possible Cause Solution
Platform does not rise.
Motor does not energize. Motor overload device
tripped or fuse blown. Reset overload relay (three-phase) or replace
fuse(s) (single-phase). Determine cause of overload.
NOTE: When replacing fuse(s), the new fuse must
have the same specification as the old fuse.
Motor starter (three-phase)
or motor relay
(single-phase) not
energizing. Check voltage at starter or relay coil.
• If voltage is present and starter or relay does not
energize, replace starter or relay.
• If voltage is not present, check all components in
series with the starter or relay coil.
4111-0008 — April 2008 28