MOTORTRONICS - Solid State AC Motor Control. Medium Voltage Soft Starts.

MOTORTRONICS Electronic Motor Brakes

MOTORTRONICS Electronic Motor Brakes

Electronic Motor Brakes

Stop AC Motor Loads Quickly and Safely… as easy as A-B-C

AC Supply Voltage
200 to 600 VAC

HP Ratings
3 to 1000 HP


Electronic braking stops the load by injecting a controlled amount of DC current into a three phase AC motor. The ABC Series “automatic braking controller” features full-wave DC braking which can be adjusted to stop your load quickly, repeatably and reliably…even if load conditions change. The ABC Series meets the three main objectives that are important in every industry: Maximized Safety, Increased Productivity and Maintenance-Free Operation.

Maximum Safety

Protect Machinery & Operators The ABC Series is designed to eliminate dangerous coast-to-stop times of rotating machines and equipment. The ABC Series also eliminates the dangerous practice of jamming the machine to bring it to a stop, which can present potential danger to operators and passers-by alike. OSHA and other safety agencies pay close attention to these types of operating conditions and recognize brakes as an important part of a system to guard against potential dangers. The ABC Series is an ideal way to add braking and eliminate dangerous “coast-to-stop” times in your application.

Increased Productivity

Stop AC Motors Quickly for a Profitable Operation Long coast-to-stop times equal lost production time. Now you don’t have to wait forever for the load to come to a stop before you make blade changes or change a tool. Simply stop your equipment using an ABC Series electronic brake for increased efficiency and product through-put. The ABC Series also eliminates any need for “plug reversing.” Reversing a load when it is still spinning creates mechanical shock which can cause equipment breakage and extended downtime. Your machinery can now do what it was designed to do… make product at a profit.

Maintenance Free Operation

Eliminate Costly Down Time Using the ABC Series electronic brake eliminates the wear and tear on mechanical brakes in the system. This means less time and money is spent replacing discs or pads (which is especially important given the “shorter life” material used in today’s mechanical brakes). Let the mechanical brake act as a holding brake and let the ABC Series do the stopping. The ABC Series eliminates the common (and also dangerous) practice of “jamming” equipment to stop the load. Expensive blades and tooling are no longer “sacrificed” to stop your motor. The ABC Series for faster, smoother stopping and maintenance free operation.

Easy to Install

The ABC Series microprocessor insures proper connections and coordinates system operation. Simply wire the ABC Series electronic brake into the motor starter circuit for a cost effective, maintenance-free means of bringing the motor and load to a stop. No isolation contactors, no additional logic wiring…it works right off the motor input leads! It’s as easy as A-B-C.

Easy to Select

The ABC Series units are sized by amperage and should be selected based on the application requirements. “Standard Duty” ratings are sized for 95 – 110% of motor FLA. “Extra Duty” ratings are sized for 150 – 250% of motor FLA. Specify maximum braking current and voltage when ordering.


Voltage Rating

Selected voltage ratings + 10%
Selectable for 50/60Hz + 2 Hz

Current Ratings

10 – 1000A in 10 sizes:
10, 24, 50, 100, 200, 300, 400, 550, 800, 1000A

Output Capacity

25% duty cycle at 100% unit rating (model dependant above 200 Amps)

Power Circuit

Full wave bridge, 4 SCRs, designed for use without isolation contactors

Transient Protection

RC snubber dv/dt circuit on each SCR device


Approved for use with existing motor starter fusing when unit is sized for motor FLA. Consult NEC for any other fusing requirements.

Control Circuit

Self-powered directly from line terminals. No separate control voltage required.

Control Method

Microprocessor unit controls sequencing. I/O monitoring and status annunciation. Braking current is adjustable via true RMS regulated
control using phase angle firing of SCRs.

Operator Adjustments

Brake Time and Jog Time = 7 position binary dipswitch
Brake Current = potentiometer

Adjustment Ranges

Brake Jog Times = 0 – 127 seconds in 1 second increments
Brake Current = Up to 100% unit rating


Starter Monitor = Dry input for auxiliary contact from motor starter.
Jumper selectable for N.O. or N.C. contact.

Brake Disable = Dry input for N.O. contact to disable braking before or during operation. Can be wired to the starter thermal overload N.O. auxiliary contact to prevent braking of overloaded motor.

Motor Power Sensor (T3) = voltage input used for sensing motor power presence in sequencing/status circuit and for zero speed sensing during braking.


Starter Coil Interlock Two sets of FORM “C” relay contacts for use
in interlocking the starter coil and/or other devices to prevent energizing
while the braking power is applied.

Mechanical Brake Release N.O. relay contact for use in controlling electro-mechanical brake as a holding brake. When the ABC is”disabled,” this circuit controls the mechanical brake normally as if it were the only brake in the system.

Aux Contact Ratings

5 amps, 250VAC max

LED Status Indicators

Large LEDs: Braking = green; Fault = red
Small LEDs: Power On, Jog/Armed, Brake Off, Disabled, Over Temp, and Wiring Error

Operating Design Temperature

0 – 50C (32-122F) open, 0 – 40C (32 – 104F) enclosed

Ambient Conditions

0 – 95% relative humidity, 0 – 3300ft (1000M) elevation


UL, cUL Listed


ABC Series Datasheet (pdf) 1.52MB
ABC Series Specifications (pdf) 61 KB
ABC Series Ratings (pdf) 397 KB
ABC Series Dimensions (pdf) 431 KB
ABC Series User Manual (Small) (pdf) 785 KB
ABC Series User Manual (pdf) 979 KB

Contact Joliet Technologies for pricing,
availability and freight options.

Phone: (815) 725-9696 or
Toll Free: (866) 492-9888
Fax: (815) 725-9393
RFQ – Request for Quote