Inovance MDBUN Series

Questions and Answers

J
Julia FosterAug 7, 2025
What to do if Inovance MDBUN shows hardware overcurrent?
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  Lisa BrightAug 7, 2025
  If your Inovance Industrial Equipment is showing a hardware overcurrent error, it could be due to several reasons. First, check for any short circuits or abnormalities in the external circuit. If found, stop the equipment and reset or power cycle the braking unit. Another cause might be a sudden or abnormal change in feedback energy, so try to reduce these sudden changes. Also, the braking unit's power could be insufficient; in that case, select a braking unit with higher power. Finally, the braking resistor might have too small resistance; select a proper braking resistor.
I
Ian JacksonAug 11, 2025
Why is my Inovance MDBUN overheating?
- E
  eortizAug 11, 2025
  If your Inovance Industrial Equipment is overheating, start by checking the air filter for blockages and ensure the fan is functioning correctly; clear the air filter or replace the fan if needed. Next, verify that the fan's power cable is securely inserted and undamaged. Also, consider whether the ambient temperature is too high and take steps to reduce it. If the power of the braking unit is too small, contact technical support engineers of Inovance.
R
Renee DavisAug 16, 2025
What causes overvoltage in Inovance Industrial Equipment?
- S
  Shannon CannonAug 16, 2025
  If your Inovance Industrial Equipment is showing an overvoltage error, it could be due to an incorrectly set input voltage class of the adaptable drive; correct it. Also, check the input feedback energy in case the feedback energy becomes abnormal. Finally, the braking unit might have insufficient capacity, so select a braking unit of higher power. If the problem persists, contact technical support engineers of Inovance.
M
Mario JamesAug 19, 2025
What to do for braking resistor open-circuit protection in Inovance MDBUN?
- A
  Abigail SharpAug 20, 2025
  If you encounter a braking resistor open-circuit protection issue with your Inovance Industrial Equipment, first verify that the braking resistor is correctly connected and functioning normally; replace it if burnt out. Also, check the IGBT to ensure it is working correctly. If the problem persists, contact technical support engineers of Inovance.
D
Daniel JohnsonAug 25, 2025
How to troubleshoot braking resistor short-circuit in Inovance Industrial Equipment?
- J
  Jonathan FletcherAug 25, 2025
  If your Inovance Industrial Equipment indicates a braking resistor short-circuit, check the braking resistor and its wiring to ensure they are normal. If the problem persists, contact technical support engineers of Inovance.
P
Patrick KingAug 28, 2025
What causes IGBT direct break-over in Inovance MDBUN?
- R
  rosesmallAug 28, 2025
  If your Inovance Industrial Equipment shows an IGBT direct break-over error, it means the IGBT module is damaged. Replace the braking unit. If the problem persists, contact technical support engineers of Inovance.
K
Kevin LinSep 2, 2025
What does reference source fault mean for Inovance MDBUN Industrial Equipment?
- M
  Mike CaseySep 2, 2025
  If your Inovance Industrial Equipment is showing a reference source fault, this indicates that the reference source for analog sampling is faulty. Replace the braking unit. If the problem persists, contact technical support engineers of Inovance.

The Inovance MDBUN Series Braking Unit is a device designed to manage regenerative energy in AC or servo drive systems during deceleration, positioning, or braking operations. When a drive performs braking, kinetic energy from the load's mechanical inertia is converted into electrical energy and fed back to the drive, causing the DC bus voltage to rise. The MDBUN braking unit consumes this regenerative energy through an external braking resistor, preventing overvoltage protection faults and potential damage to the drive, thus ensuring its normal operation.

Function Description:

The braking unit's core function is to maintain the drive's DC bus voltage within a secure range during regenerative braking. It achieves this by discharging excess electrical energy through an external braking resistor when the bus voltage exceeds a predefined "braking start voltage" (P0-00). The discharge continues until the bus voltage drops below a "braking stop voltage" (P0-01). The "start braking rate" (P0-02) can be adjusted to control the discharge rate and, consequently, the braking time. The unit can operate in a master/slave configuration, allowing multiple braking units to be deployed in parallel for high-power drive applications. In master mode, the DI terminal acts as a block input, stopping the unit and blocking output when valid. In slave mode, DI serves as a start/stop signal input, initiating braking when valid and stopping when cancelled. The DO terminal outputs a running/stop signal to the slave unit. Fault conditions are indicated via TA/TB/TC relay contacts.

Important Technical Specifications:

The MDBUN series offers various models with different input voltage classes (220 VAC, 380 VAC, 480 VAC) and braking capacities. For instance, models like MDBUN-45-S, MDBUN-60-S, and MDBUN-90-S are designed for 220 VAC systems, offering continuous braking currents of 45A, 60A, and 90A respectively, with corresponding maximum continuous braking powers of 21kW, 27kW, and 41kW. Minimum braking resistances range from 8Ω to 4Ω for these models. Similarly, MDBUN-T models cater to 380 VAC systems, and MDBUN-5T models to 480 VAC systems, with proportional current, power, and resistance specifications. The unit's installation environment requirements include an altitude below 1000m (with derating up to 4000m), ambient temperature between -10°C and +40°C, humidity below 95% RH (non-condensing), and vibration less than 5.9 m/s² (0.6 g). Storage temperature is -20°C to +60°C. It has a pollution level of 2, uses air cooling, and has an ingress protection level of IP20.

Usage Features:

The MDBUN braking unit is suitable for a wide range of large-inertia applications requiring sudden stops, such as elevators, textile machines, paper making machines, centrifuges, wire drawing machines, winding machines, proportional linkage systems, and crown blocks. Installation involves ensuring proper clearances (10 cm top/bottom, 5 cm sides) for heat dissipation and mounting on incombustible surfaces. It must be installed upright, not upside-down or horizontally. When multiple units are used, they should be installed side-by-side, or with an insulation guide plate if stacked. Wiring requires careful attention to DC bus polarity, proper grounding (resistance < 4Ω), and cable lengths (braking unit to drive < 5m, twisted-pair; braking unit to resistor < 10m). The unit features a front panel with PWR (power), RUN (running), and ERR (fault) indicators. An optional external operation panel allows for parameter setting and status monitoring. The operation panel has a 5-digit LED display for bus voltage, maximum continuous braking current, IGBT module temperature, present braking rate, and fault codes. It also includes keys for programming (PRG), confirmation (ENTER), increment/decrement, shift, and reset (STOP/RES). The menu structure is three-level, allowing access to function code groups (Level I), function codes (Level II), and setting values (Level III). Parameters in function code group P0 (P0-00 to P0-06) are critical for initial setup, including braking start/stop voltages, braking rate, and master/slave mode selection.

Maintenance Features:

The manual emphasizes thorough reading and understanding before installation, wiring, operation, maintenance, and inspection to prevent personal injury or death. Safety precautions are graded as DANGER (severe personal injury/death) and WARNING (personal injury/property damage). Key safety instructions include:

Do not install if damaged or if packing list doesn't match.
Handle with care to prevent damage.
Do not touch components with bare hands to avoid static electricity damage.
Install on incombustible objects, away from flammable materials.
Do not loosen fixed screws, especially those with red marks.
Do not drop wires or screws into the unit.
Install in vibration-free, direct sunlight-free locations.
Ensure proper cooling when multiple units are in the same cabinet.
Keep the unit close to the drive with twisted cables not exceeding 5m.
Wiring must be performed by qualified personnel with power supply cut off.
Ground the device properly.
Connect DC bus terminals correctly to avoid damage.
Use recommended wire sizes and ensure EMC compliance.
Never connect the braking resistor between DC bus terminals (+) and (-).
Verify power supply voltage class consistency and secure wiring.
Do not perform voltage resistance tests on the unit.
Cover the unit before power-on.
Connect all peripheral devices properly.
Do not open the cover after power-on.
Avoid touching strong-current terminals after power-on.
Do not touch the externally connected braking resistor.
Do not touch the fan or braking resistor to check temperature during operation.
Signal detection must be performed by qualified personnel.
Repair/maintenance only by qualified personnel, after ensuring input bus voltage is below 36 VDC and 5 minutes after power-off to allow capacitor discharge.
Re-set parameters after unit replacement.
Plug/remove components only after power-off.

Routine maintenance includes checking the installation environment, cooling fan operation, vibration, and overheating. Routine cleaning involves keeping the unit clean, removing dust (especially metal powder), and clearing oil stains from the cooling fan. Periodic inspection covers checking and cleaning the air filter, tightening screws, checking for corrosion, inspecting wiring terminals for arc signs, and performing main circuit insulation tests (after disconnecting from the braking unit and using a 500 VDC megameter). The cooling fan is a vulnerable part with a service life of 2 to 3 years, and replacement is recommended if cracks appear on the blade or abnormal vibration noise occurs. For long-term storage, the unit should be packed in its original box and energized every 2 years for at least 5 hours, with the input voltage slowly increased using a regulator, to prevent electrolytic capacitor degradation. The product comes with an 18-month warranty, with charges for damages due to improper operation, environmental factors (fire, flood, abnormal voltage), or non-recommended functions.