Type BM Braking Modules
Application
AC variable frequency drives are commonly used
with general purpose AC induction motors to
form reliable variable speed drive systems.
Problems with these drive systems can occur
when an application requires a deceleration rate
faster than what can be managed by the drive
alone, or when motor speeds exceed the
synchronous speed set by the output frequency
of the drive (which is called an overhauling load
condition). Both of these conditions create
regenerated power which flows from the motor
back into the drive, causing its DC Bus to rise.
To manage the regenerated power and avoid
shutting the drive down due to an over-voltage
trip, this power must be dissipated by an external
braking resistor. Braking Modules are used in
conjunction with an AC drive to monitor the DC
bus of the drive and activate external braking
resistor as needed.
Product Overview
Ω
PowerohmTypeBM
BrakingModule
DANGER: HIGHVOLTAGE
Brakingmodulecontainslethal voltageswhen
connectedtotheinverter. Power totheinverter must
beremovedbeforeservicingthebrakingmodule.
Allowadequatetime(approximately10minutes) after
removingpower beforetouchinganycomponents.
ThePOWERONLEDmust becompletelyout before
servicingtheunit.
EXTERNAL
Slave
Master
INTERNAL
VoltageLevel Jumper
BrakeEnable
Jumper
CLASS JP1 JP2 JP3 JP4 JP5
200
400 380 400 415 440 460
600
Master - Slave
Jumper
POWERON(GREEN)
Fault Contact
Jumper
TURNONLEVEL(ADJ.)
NCNO
BRAKING(GREEN)
External
FAULT(RED)
BrakeEnable/
Slave Fault Master
FanPower
Input Output Output
120VAC
+ + 1 2 3 4 5 6 7 8 9 10
N[DC-] P[DC+]
15ft. max
G
G
PO[1] B[2]
30ft. max
A typical AC Drive, Braking Module and Braking Resistor
configuration is shown above.
The Powerohm Type BM Braking Module is available
in three different voltage classes including 240, 480
and 600 volts with continuous current ratings available
in 50 and 115 amps. The Type BM Module can be
used in conjunction with any AC Drive not only
to avoid over-voltage trips, but to greatly
improve the performance of the drive system.
The use of Braking Modules and resistors
increase the braking torque capability of a
variable frequency drive, allowing faster and
more controlled deceleration times. To
accommodate higher horsepower system
requirements beyond the capability of a single
Module, the Modules are all Master/Slave
programmable.
125 W 34th Street, Covington, KY 41015
Toll Free: (800) 838-4694
Ph: (859) 384-8088, Fax: (859) 384-8099
Email: sales@powerohm.com
Visit us on the Web: www.powerohm.com
Type BM Electrical ratings & dimensions
Electrical Specifications
Dimensions
1.69
TABLE 1: General Specifications for Powerohm
Type BM Braking Modules
Powerohm
Part No.
BM230S
Nominal AC
Line Voltage
240
RMS
Continuous
Load Current
50
Ω
Turn
ON
Voltage
390
Powerohm Type BM
Braking Module
Max Peak
Current
DANGER: HIGH VOLTAGE
Braking module contains lethal voltages when
connected to the inverter. Power to the inverter must
be removed before servicing the braking module.
Allow adequate time (approximately 10 minutes) after
removing power before touching any components.
The POWER ON LED must be completely out before
servicing the unit.
External
9.00
200
Master
Brake Enable
Jumper
CLASS JP1 JP2 JP3 JP4 JP5
200
240
400 380 400 415 440 460
600
600
12.75
Slave
Internal
Voltage Level Jumper
Master - Slave
Jumper
11.00
11.00
POWER ON (GREEN)
Fault Contact
Jumper
TURN ON LEVEL (ADJ.)
NC NO
BM280S-F*
240
115
390
200
BM430S
480
50
775
200
BM480S-F*
480
115
775
200
BM630S
600
50
970
200
BM680S-F*
600
115
970
200
BRAKING (GREEN)
Slave
Input
+
1
2
intermittent duty cycles, as long as the Module RMS
Load Current rating is not exceeded. RMS Load Current =
Fault
Output
3
N[DC-] P[DC+]
1.00
Note: Peak currents up to the maximum are allowed at
External
Brake Enable/
Fan Power
FAULT (RED)
4
Master
Output
+
5 6
G
120VAC
7
G
8
PO[1]
9
10
B[2]
5.88
5.13
6.38
5.13
0.15
6.38
Peak Current X the square root of duty cycle.
* The cooling fan option is necessary to achieve the 115 amp
rating and requires 120V Control Power for fan.
Environmental Conditions
Ambient Temperature Range: -10ºC to 40ºC Maximum
Altitude: 3300 feet (1000m)
Maximum Vibration: 10 to 20Hz, 32ft/sec/sec; 20 to
50Hz, 6.5 ft/sec/sec
Weights
BM30 Series without fan: 8 lbs.
BM80 Series with fan: 10 lbs.
For detailed specifications and mounting instructions download a copy
of the Type BM Installation Manual on the web at: www.powerohm.com.
125 W 34th Street, Covington, KY 41015
Toll Free: (800) 838-4694
Ph: (859) 384-8088, Fax: (859) 384-8099
Email: sales@powerohm.com
Visit us on the Web: www.powerohm.com