Selection Of Motor Starter - Maxwell 6000 Series Manual

groove of the Chainwheel.
• Slide Upper Clutch Cone. Note that this cone has
friction lining, which SHOULD NOT be greased,
unlike the lower cone.
• Assemble Drum on top of the clutch cone (VWC
models only).
• Assemble Clutch Nut.
• Put Retaining Washer on top of the Mainshaft
and secure it with the Screw.
• Insert Cap into the Clutch Nut.
2.5

SELECTION OF MOTOR STARTER

Several AC motor starter options for windlasses are
available, each with characteristic current demands
and start load limitations. Maxwell recommends that
selection of the best motor start system be entrusted
to experienced persons familiar with anchoring
procedures and the vessels generating capacity.
"Direct On Line" starter is the simplest way of starting
an AC motor and it will allow the windlass to start
under full rated load. However, this method requires
relatively high momentary starting current, which the
generators may have adverse effect to the rest of
the electrical system on board. See specifications
for current values at 400V in Section 1.3 and make
sure to recalculate it for the voltage used on board.
Start current may be limited to about half the above
amount by using a "Star-Delta" starter. However, start
torque is thereby limited to loads of about 25-30% of
the windlass rated capacity.
"Star-delta" and "soft starters" are not recommended
for starting windlass motors, as the motor torque is
severely limited during start up period. Since these
motors often have to start under load (when retrieving
the ground tackle), they might not be able to move
until they reach the full voltage and torque. The
benefit of starting at lower current would therefore be
lost. Also, the motor brake would release immediately
on start-up, which could cause short movement of the
chain in opposite direction.
The Variable Frequency Drives (VFD) offer accurate
control of current during start up period while keeping
high motor torque. They also offer various other
benefits like:
• infinite speed control
• running the windlass over its nominal speed
• accurate current overload and thermal overload
control
13
The selection of the type of motor starter
should be done by a qualified electrical
engineer, taking into consideration the power
generating capacity on board.
Maxwell offers both advice and different types
of custom made starters to complement our
windlasses.
The "up" and "down" start contactors must
be mechanically or electrically interlocked
to safeguard the motor, in the event that an
accidental attempt is made to start the motor
in both directions simultaneously.