Brake resistors and dynamic braking units help variable frequency drives provide controlled deceleration for high-inertia and overhauling loads. Brake resistors convert regenerative energy produced by the motor into heat, helping reduce DC bus overvoltage faults and shorten stopping times. Resistors are available for AC drives up to 600 VAC and in ratings up to 22.5kW. They are available in many mounting styles and enclosures, including outdoor-rated models. Dynamic braking units work with compatible drives to manage regenerative energy on drives without built-in braking circuitry.

AutomationDirect GS Series Brake Resistors

Brake resistors increase the AC drive's braking torque for frequently repeated ON/OFF cycles or for decelerating a load with large inertia. Brake resistors are compatible with various AC drives (check specifications for selection).

• Power ratings from 80W to 9.6kW support a wide range of drive sizes, braking demands, and duty cycles
• Resistance ratings from 3.3 to 750 ohms simplify matching across the AutomationDirect drive lineup
• Encapsulated, panel-mount, and NEMA 1 enclosed options provide installation flexibility, with select models featuring a temperature switch for overtemperature monitoring

Crohm Brake Resistors

Crohm brake resistors are designed and manufactured in the USA with ISO 9001 certification. These brake resistors can be used with any AC drive up to 600 VAC class (check specifications for selection). All NEMA 1 and NEMA 3R models include a built-in temperature switch.

• Flat-mount, open-coil, finger-safe NEMA 1, and outdoor-rated NEMA 3R models span 200W to 22.5kW, providing space-saving, economical, and applicationappropriate options for diverse installations and braking requirements
• Resistance ratings from 3.7 to 400 ohms simplify matching with drives from many manufacturers
• Corrosion-resistant stainless steel bus bars promote long-term reliability
• Prewired terminal blocks simplify installation and reduce wiring time
• Compliant with applicable CSA C22.2 and UL 508 standards
• CE marked

Durapulse GS Series Dynamic Braking Units

DURApulse GS series dynamic braking units work with GS series braking resistors to dissipate regenerative energy during motor deceleration on compatible DURApulse AC drives. Models support 230 VAC and 460 VAC drive systems with motor capacities from 20 to 250hp, providing a selection path for applications requiring controlled deceleration of high-inertia or overhauling loads.

• Models support maximum motor capacities from 20 to 250hp [15 to 185kW], simplifying selection based on drive voltage and connected motor capacity
• Maximum discharge currents from 40 to 225A at a 10% duty cycle provide powerful braking for short-duration stops of up to 10 seconds
• Continuous discharge currents from 15 to 100A support a wide range of braking demands and application duty cycles
• Wall-mount enclosures feature IP50 protection for GS-1DBU through GS-4DBU and IP10 protection for GS-5DBU through GS-7DBU, with a 14°F to 122°F [-10 to +50°C] operating range for reliable performance in varied industrial environments.

Line and load reactors help protect equipment and optimize AC drive performance. Input-side line reactors help prevent nuisance tripping, improve power factor, reduce downtime, and protect sensitive equipment. Output-side load reactors smooth motor current, reduce voltage spikes and reflectedwave damage, protect motor insulation, and help motors run cooler. They are recommended for non-inverter-duty motors and drive-to-motor wiring up to 100 feet. For distances over 100 feet, use a VTF series dv/dt output filter. Reactors are stocked for free 2-day delivery on all orders over $49, and cross-reference charts simplify matching them to AutomationDirect VFDs

AutomationDirect Line/Load Reactors

AutomationDirect LR/LR2 series reactors provide versatility to function as either line or load reactors for any VFD application. Load-side applications are recommended with wiring lengths of 100 feet or less.

• Line- or load-side use with 230/460/575 VAC three-phase applications up to 370A (300hp @ 460 VAC) protects most three-phase, low-voltage drives and motors
• Line-side use with 120/230 VAC single-phase applications up to 25A (3hp @ 230 VAC) provides added input protection for many single-phase VFDs
• Optional DIN rail mounting for select models simplifies installation

Block USA Line and Motor Reactors

BLOCK USA line and motor reactors deliver economical and high-performance protection for any VFD application. Line and motor-specific designs with broad specifications allow fine-tuning of your application from technical design to cost. Featuring innovative winding technology and a broad voltage and amperage range, these reactors help optimize system performance while reducing power losses and installation costs.

LR3 series line reactors

• Support 200 to 600 VAC three-phase applications up to 250A (225hp @ 460 VAC), providing line protection across a broad range of VFD sizes
• Available with 3% or 5% impedance for general VFD protection, higher harmonic levels, or applications with tighter power-quality requirements
• Lightweight aluminum construction and high-efficiency windings on models rated 80A and higher simplify handling and reduce power losses

NKE series line reactors

• Support 120/230 VAC single-phase applications up to 25A (3hp @ 230 VAC),providing added input protection for many single-phase VFDs

MR3/MDB motor reactors

• Support 200 to 600 VAC three-phase applications up to 110A (100hp @ 460 VAC), helping protect motors from damaging output-side voltage effects
• MDB models rated 72A and higher support 120 Hz output and motor leads up to 150 meters with shielded cable, eliminating the need for a dv/dt filter in some applications

AutomationDirect VTF Series Output Filters

VTF series output (dv/dt) filters provide protection against harmful reflected waves between the VFD output and an AC motor. They are recommended when motor protection is critical or when motor wiring distances are over 100 feet and up to 1,000 feet. The filters ensure voltage spikes are limited to below 1,000 V. Output filters also provide other benefits, such as reduced motor heating, increased motor bearing life, and reduced common-mode current.

• Support 208 to 600 VAC applications to protect many VFD-controlled, low-voltage motors
• Current ratings up to 362A accommodate numerous drive and motor combinations
• NEMA 1 versions mount outside the control panel to conserve enclosure space and reduce cooling requirements