DC Hoist Motor, Brake, and Encoder/Tachometer
42-02-7223 C1 2-11
2
iControl DC
Verifying Brake Current Resistance
High current brake systems use a brake (iField) module.
1. With brake leads disconnected from the controller, measure resistance through the
brake coil.
2. Inside the controller cabinet, locate the screws, one at the top and one at the bottom
right corner of the iPower box (the enclosure the iBox is mounted to). Turn the screws
counter-clockwise to their stops and open the enclosure (it is hinged on the left).
3. Refer to job print drawing D2. Toward the right-top of the enclosure, locate the large
ceramic resistor labeled RB.
4. Check the resistance across RB. As an initial working value, RB resistance should be
about three times (3 X) the resistance measured across the brake coil.
During adjustment, the resistance across RB may be further adjusted to achieve smooth brake
setting. Too little resistance causes the brake to remain picked for too long. Refer to your job
prints for instructions.
5. If necessary, adjust RB resistance by loosening and sliding the center-tap up or down.
When the resistance is correct, retighten the center tap.
Wiring the Brake
• Refer to job print drawing D2. Connect brake wires to terminals B1 and B2 located just
below the iPower box.
Brake wires must not be routed in the same conduit with DC motor wires or velocity encoder
wires.
Tachometer or Encoder Installation and Wiring
A tachometer or a velocity encoder may be used.
Tachometer
(If you are using a velocity encoder, please see the next topic.) When installing a tachometer, do
not mount it near a magnetic field (for example, the motor field coils). Magnetic fields may
cause the tachometer to report incorrect speeds. Note also that any vibration caused by the
tachometer cannot be corrected inside the drive. The tachometer wheel and the surface on
which it runs must be smooth and the tachometer must be mounted so that it can maintain con-
tact without binding or bouncing.
Table 2.2 Selecting a Tachometer or a Velocity Encoder
Machine Device Shaft Mounting Brake Drum Mounting Sheave Mounting
Geared Tachometer Yes No No
Encoder Yes 1024PPR No No
Gearless Tachometer No Yes Yes
Encoder Yes 12,700PPR Yes 1024PPR Yes 1024PPR
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