Deceleration braking
Rapid speed reduction pushes energy back into the DC bus and can trigger overvoltage faults.
Motor Testing Solution
Bidirectional Power Supply for Motor Testing
When your motor generates back-fed energy during braking, ordinary DC sources fail. Safely absorb, control, and recycle regenerative energy back to the grid with FaithTech’s smart bidirectional power solutions
95%
Regeneration efficiency
3X
Recommended power margin
0-3MW
Scalable system power
Problem diagnosis
When a motor becomes a generator, your DC bus needs an escape path.
Passive back-driving
An external load or dynamometer can force the motor to generate energy during validation.
Regenerative braking
Continuous regen cycles create heat and wasted energy when a braking resistor is the only escape path.
Emergency stop
Fast stop profiles can create short, high-power energy spikes that stress ordinary DC sources.
Architecture choice
Braking resistor workaround or regenerative power platform?
The right choice depends on braking frequency, peak regenerated power, and whether your bench needs continuous automated testing.
During braking or regenerative operation, motors generate energy. Only a bidirectional power supply can absorb and reuse this energy safely and efficiently.
Unidirectional Power Supply
Only Output (One-way)
Can only supply power to the motor. Cannot absorb energy returned from the motor.
Source
Power Flow
Cannot Absorb: Overvoltage Risk
Regenerated Energy
Motor
Limited Testing Scenarios
Can only test basic motoring drive; cannot validate heavy deceleration or high-inertia stops.
High Risk of Overvoltage
Back-fed braking energy forces DC bus voltage to spike, risking damage or system trip.
Energy Wasted as Heat
Requires bulky braking resistors to burn off regenerative energy, creating massive heat load.
Higher Operating Cost
All braking energy is lost. Requires extra air conditioning and ventilation to handle resistor heat.
Bidirectional Power Supply
Source & Sink (Two-way)
Can both supply power to the motor and absorb/reuse energy generated by the motor.
Source
Power Flow
Absorb & Reuse: Return to Grid
Regenerated Energy
Motor
Full Test Coverage (Drive & Regen)
Seamless cross-quadrant switching allows testing motoring, braking, and fast speed reversals.
Safe & Reliable Operation
Active DC bus regulation absorbs energy spikes instantly, preventing safety trips and overvoltage.
Energy Recovery & Reuse
Feeds braking energy back to the AC grid with up to 95% efficiency, reducing site power draw.
Lower Operating Cost
Zero wasted energy, no resistor cooling needed, and zero maintenance for auxiliary dump loads.
Bidirectional Power Supply Enables More Comprehensive and Reliable Motor Testing
Drive Testing (Motoring)
Regenerative Braking Testing
Dynamic Load Simulation
Battery Charge/Discharge Testing
EV Powertrain Testing
E-Motor & Inverter Testing
More Efficient & Safer
Decision point
Unidirectional source + resistor
Bidirectional regenerative source
Back-fed energy
Absorbed by braking resistor or protection circuit
Accepted directly by the bidirectional source
Heat
High heat load and extra cooling demand
Lower heat because energy returns to the grid
Continuous braking
Limited by resistor sizing and thermal rise
Designed for repeated source and sink operation
Setup complexity
More wiring, more protection, more validation risk
One regenerative source replaces source plus dump load
Energy cost
Motor braking energy is mostly wasted as heat
Up to 95% regenerative efficiency in suitable systems
Failure risk
DC bus spikes can damage power stages
Stable DC bus control during braking events
FaithTech system architecture
Size the source for both drive power and regenerated braking energy.
For motors above 6kW, frequent braking profiles, or back-to-back benches, start with a bidirectional source and verify peak regenerative power before final rack sizing.
Grid
AC input and recovered energy path
Bidirectional DC source
FTB / FTDM source-sink control
Inverter / controller
DC bus, PWM drive and protection
Motor / dynamometer
Drive, braking and back-drive profiles
Selection logic
- Motor rated power is 6kW or higher.
- The test includes frequent deceleration or emergency stop cycles.
- A dynamometer or external load can back-drive the motor.
- The bench needs continuous automated tests without resistor cooldown.
- Energy cost and heat management matter in production validation.
Recommended FaithTech products
Start with these bidirectional DC platforms.
FTB9000 Series
Bidirectional | ±180kW | ±4500A | 2250V
- 0-2250V Voltage
- Up to 180kW per unit Power
- MW-level parallel benches System
FTDM Series
bidirectional power modular
- 3U / 60kW Module
- High-power modular systems Scale
- ATE and production benches Use Case
FTB7000 Series
Bidirectional programmable DC power source
- Source and sink Mode
- Motor controller testing Use Case
- Frequent braking cycles Feature
Solution consultation
Not sure how to size your motor test power system?
Share motor power, braking profile, DC bus voltage, and test cycle. FaithTech can help recommend the right bidirectional source and system margin.
Reduce resistor heat
Recover braking energy
Protect the DC bus