BDC30A Series
DESCRIPTION: The BD25A20AC Series PWM servo amplifiers are designed to drive brushless DC motors at a high switching
frequency. They are fully protected against over-voltage, over-current, over-heating and short-circuits. All models interface with digital
controllers that have a digital PWM output. PWM IN determines the output duty cycle. DIR IN determines the direction of rotation. They
require a single AC power supply. A single red/green LED indicates operating status. The current limit can be set by DIP switches.
SPECIFICATIONS:
All BD25A20AC specifications are identical to the BD25A20 specifications (see BD30A Series) except for:
MODEL
POWER STAGE SPECIFICATIONS
BD25A20AC
AC SUPPLY VOLTAGE
30 - 125 VAC, 50 – 60 Hz
SHUNT RESISTOR
10 Ω @ 50 W
185 VDC
SHUNT SWITCH ON VOLTAGE
BUS CAPACITANCE
3600 µF
SHUNT FUSE (d = .25 inches, L = 1.25 inches)
BUS FUSE (5x20 mm)
3 A Motor Delay rated @ 250 VAC
16 A slow-blow rated @ 250 VAC
MECHANICAL SPECIFICATIONS
POWER CONNECTOR
SIGNAL CONNECTOR
Screw terminals
Molex connector
7.35 x 4.23 x 2.45 inches
186.7 x 107.4 x 62.2 mm
2.5 lb.
SIZE
WEIGHT
1.14 kg
These amplifiers contain a rectifier bridge and filter capacitors to generate the DC bus internally from the AC input power. The
DC bus voltage is 1.4 times AC voltage (RMS), e.g. 170 VDC from 120 VAC. During braking much of the stored mechanical
energy is fed back into the power supply and charges the output capacitor to a higher voltage. If the charge reaches the
amplifier's over-voltage shutdown point, output current and braking will cease. To ensure smooth braking of large inertial loads,
a built-in "shunt regulator" is provided in the BD25A20AC. The shunt regulator will switch-on the internal power resistor when
the bus voltage reaches 185 VDC. This resistor then dissipates the extra energy of the DC bus.
APPLICATION NOTE: Contact factory for information regarding the use of the current monitor pin (P1-15).
OPTICAL INPUT SIGNAL ISOLATION: PWM, DIR, INH, FAULT inputs are always isolated from the power section. On the
BD25A20AC series the Hall sensor inputs (P1-10 through 14) are also isolated.
ORDERING INFORMATION:
Models: BD25A20ACX
X indicates the current revision letter.
TYPICAL SYSTEM WIRING: See section “G”.
MOUNTING DIMENSIONS: See page F-11.
B-26