Industrial Engineer · phase 11 of 16
Torque Boost
Additional low-frequency voltage used to compensate stator resistance and improve starting or low-speed torque.
The Explain card
- Plain English
- Torque boost adds extra voltage at low frequencies, above the plain volts per hertz line. It makes up for the voltage lost in the stator resistance, which matters most when the frequency and voltage are both small.
- Example
- A screw conveyor stalls trying to start at 3 hertz in V/Hz mode. A few percent of torque boost puts enough flux in the motor to break it loose.
- Why it matters
- Boost is a fix for weak starting in scalar control. Too much of it saturates the motor and overheats it at low speed, and vector modes do the same job automatically, so if you find yourself cranking boost up, the control mode is probably the real problem.
- Hook
- A little extra voltage where the curve runs out.
Where it sits in the deck
Phase 11: VFD Control Modes and Tuning
How a drive decides what to send the motor, from plain volts per hertz up to closed loop vector control, and how each mode is tuned.
