Nabrico DF-1 N Series, Owner'S Manual

Page: 58 / 72

58
NABRICO DF-1 N ELECTRIC WINCH Owner’s Manual
OM-DF1-021-A
MOTOR BRAKES
INSTALLATION & MAINTENANCE
RETAIN FOR FUTURE USE U35000 - 3 of 19
www.nord.com/docs 06.13.16
NORD Gear Corporation
Toll Free in the United States: 888.314.6673
NORD Gear Limited
Toll Free in Canada: 800.668.4378
Brake Control Rectifiers
NORD brake control rectifiers convert AC voltage to DC volt-
age. Rectifiers are used because most applications require
AC voltage to power the motor, but DC power is required
to power the brake and DC power is not typically available.
NORD brake motors typically include the rectifier located in-
side the terminal box.
Rectifier Advantages
• Individual power source for each brake.
• Compact size, mounted inside the terminal box.
• Multiple types, voltage options and release/engagement
modes available.
• Mountable in a separate control cabinet.
• Integral protection against voltage spikes.
Table 3: Rectifier Types and Ratings
Model Type Part No. Color Input
Voltage
Rated
Current
V
AC
± 10% A
DC
(40°C) (75°C)
GVE20L Full-wave 19141000 Black 110-275 1.5 1.0
GVE20V Full-wave 19141030 Black 110-275 1.5 1.0
GHE40L Half-wave 19141010 Yellow 200-480 2.0 1.0
GHE40V Half-wave 19141040 Yellow 200-480 2.0 1.0
GHE50L Half-wave 19141020 Gray 200-575 2.0 1.0
GHE50V
Half-wave 19141050 Gray 200-575 2.0 1.0
GUE40V Dual-wave 19140300 Black 230-460 0.7 0.5
PMG500 Push-Hybrid 19140200 Black 200-500 4.0 2.8
Rectifier electronics are sealed for moisture-protection; electronics on models end-
ing with the suffix “V” are resin-encapsulated to provide added protection if water
should get into the motor terminal box.
Rectifier Types
Full-wave rectifier [GVE]:
A rectifier in which both the positive and negative half-cycles
of the AC input signal are rectified to produce a uni-direction-
al DC current supply to the load or the brake. The output volt-
age is 90% of the input voltage (V
DC
= 0.90 x V
AC
).
Half-wave rectifier [GHE]:
A rectifier in which only alternate half-cycles of the AC input
signal are rectified to produce a uni-directional DC current
supply to the load or the brake. The output voltage is 45% of
the input voltage (V
DC
= 0.45 x V
AC
).
Dual Wave Rectifier [GUE]
A rectifier that can be wired as either a full-wave rectifier or a
half-wave rectifier depending upon how it is connected to the
AC input signal.
IMPORTANT NOTE
If the motor is connected to a frequency inverter, soft start,
or is a two-speed motor, then seperate AC power must be
supplied to the brake rectifier.
Rectifier Types [Ctd.]
PMG 500 Push-Hybrid rectifier [PMG]:
A fast-acting or push-hybrid brake rectifier provides an ini-
tial “push” in the form of a timed full-wave brake-release
function, which is then followed by a continuous half-wave
brake-holding function. There are two ways to apply these
rectifiers as follows:
• “Overexcitation” of the brake coil provides faster brake
release or improved cycling capacity. The DC voltage of the
brake coil is determined based upon using a half-wave
rectifier. The output voltage is 45% of the input voltage
(V
DC
= 0.45 x V
AC
).
• “Reducer-Power Holding” of the brake coil maintains the
brake in a released state by using only 25% of the power
needed for the initial brake release. This results in very
fast brake stopping. The DC voltage of the brake coil is
determined based upon using a full-wave rectifier. The
output voltage is 90% of the input voltage.
(V
DC
= 0.90 x V
AC
).
NORD offers additional fast-acting rectifiers besides the PMG
500. For additional details please reference User Manual
U35100 – Fast Acting Brake Rectifiers.
IMPORTANT NOTE
In order to prevent rapid wear, the PMG 500 rectifier is
required when utilizing the larger 800 Nm (590 lb-ft) and
1200 Nm (885 lb-ft) twin-rotor brakes. The PMG 500 rec-
tifier is wired to “overexcite” the brake during its initial
release.
Brake Switching Options
The rectifiers discussed in this manual can be wired to allow
brake switching at either the AC power source (input) or the
DC power source (output).
• AC switching allows the brake rectifier to be powered
directly from the motor’s terminal block with no additional
wiring. However, this provides a slower brake stopping
time due to the additional time needed to de-energize or
collapse the motor’s magnetic field.
• DC switching directly interrupts the current flow in the DC
circuit of the brake rectifier. This method of brake switch-
ing guarantees faster brake stopping or brake engage-
ment times.
WARNING
When the moving system undergoes a change in height
(such as in a lift or incline conveyor application) or if the
system tends to speed up or overhaul during normal oper-
ation, then DC-switching of the brake is required in order
to prevent excessive load movement, drift or falling loads
during stopping.