MBVA 3300W to 8500W Series Mini Braking High Power Resistor Assemblies

What are the MBVA 3300W to 8500W Series Mini Braking High Power Resistor Assemblies?

The MBVA is a high-power metal-clad wire-wound resistor assembly engineered for industrial drive systems and renewable energy applications that demand higher power dissipation than a single-element braking resistor can provide. Each MBVA unit combines two, three, or four individual high-power resistors housed within partial steel end covers, forming a compact integrated assembly that delivers continuous power ratings from 3.3kW up to 8.5kW — while retaining the chassis-mount profile and bolt-down simplicity of a standard metal clad resistor.

Five assembly configurations cover a continuous power range of 3.3kW to 8.5kW at 25°C, with short-duration pulse capability from 13kW up to 135kW depending on model and duty cycle (referenced to a 120-second cycle duration). The resistance range of 0.5Ω to 100Ω addresses the impedance requirements of industrial braking chopper circuits and wind turbine dump loads, with extended ohmic ranges available on request. Tolerance options of ±5% and ±10% are available, with a temperature coefficient not exceeding ±260ppm/°C.

The assembly's maximum surface temperature rating of 350°C and a working voltage of 600VAC confirm suitability for industrial drive bus voltages. Dielectric strength is tested at AC 1500V or 2500V for 1 minute (2mA maximum leakage current), and insulation resistance is guaranteed at 20MΩ minimum. A built-in thermostat and terminal box are both available as options, making the MBVA well suited to enclosed cabinet installations where over-temperature protection and clean wiring termination are required. The short-time overload rating of 5–10× rated power for 5–10 seconds accommodates the intense repetitive pulse loads characteristic of braking duty cycles in industrial drives.

Braking & dump load application note: In variable-speed drive systems, the MBVA is connected across the DC bus through a braking chopper IGBT. During motor deceleration or emergency stop events, regenerative energy raises bus voltage above the regulation threshold, triggering the chopper to switch the MBVA into circuit. The assembly absorbs this energy as heat, clamping the DC bus within safe limits and protecting drive electronics from overvoltage faults. In wind turbine applications, the MBVA functions as a dump load resistor — dissipating excess generated power during grid faults or turbine overspeed events when energy cannot be fed to the grid. The multi-element construction of the MBVA allows significantly higher power ratings than a single-body resistor within a footprint that remains practical for panel or frame mounting.

Model: MBVA
Resistor type: Metal clad resistor
Description: Assembly
Power Rating: 3.3kW-8.5kW
Resistance (Ω): 0.5~100
Tolerance (%): ±5, ±10
TCR (ppm/C): 260 Max.

Model: RA
Resistor type: Metal clad resistor
Description: Assembly
Power Rating: 80W~750W
Resistance (Ω): 0.1~2.2k
Tolerance (%): ±0.5, ±1, ±2, ±5, ±10
TCR (ppm/C): 260 Max.

Model: HRA
Resistor type: Metal clad resistor
Description: Assembly
Power Rating: 520W-2500W
Resistance (Ω): 0.1~1.6k
Tolerance (%): ±0.5, ±1, ±2, ±5, ±10
TCR (ppm/C): 260 Max.

Model: MCS
Resistor type: High Power Braking
Description: Industrial
Power Rating:2kW-3.4kW
Resistance (Ω): 0.1~9k
Tolerance (%): ±1, ±5, ±10
TCR (ppm/C):

Model: IRVA
Resistor type: Metal clad resistor
Description: Chassis mounted assembly
Power Rating: 300W-450W
Resistance (Ω): 30~15k
Tolerance (%): ±1, ±2, ±5, ±10
TCR (ppm/C): 260 Max.