Now Available: On-Demand Webinar—Software-Controlled Switched Reluctance Motor

On Demand Webinar and Slides


Software-Controlled Switched
Reluctance Motor

If you missed our last webinar, “Software-Controlled Switched Reluctance Motor,” you can now access a recording of it in the Emerging Building Technologies YouTube Channel. You can also view a copy of the presentation slides.

Thanks to all the presenters and to the participants for their thoughtful questions, some of which are answered below.



Q: Does the $2,430 price for the 10 hp motor include the motor controller and software?
A: Yes. At the test-bed site the combined motor and controller was 44% less expensive than a code-compliant premium efficiency motor and VFD.

Q: How does this motor tie to a BMS? Can it talk BACnet, for example?
A: The motor controller can be controlled through proprietary cloud software or connected to a BMS system via BACnet and Modbus, with support for other protocols in development.

Q: Do you need to connect a computer to set the smart motor up?
A: For the model tested in San Ysidro, a computer was needed to change parameters on site. A mobile application that will allow configuration and control is under development. Currently, most smart motor systems are pre-configured and delivered with parameters already set. One benefit of not having controls directly accessible from the controller is that it prevents unauthorized changes. Informal interviews with facility managers, building engineers, and HVAC technicians suggest that between 30% and 50% of VFDs are bypassed in the field.

Q: If the motor controller gets damaged, say from an electrical spike, can the controller be replaced independent of the motor itself?
A: Yes, the motor controller and motor are two separate units.

Q: Can the motor continue to run if the controller fails?
A: All switch reluctance motors require a motor controller to operate. Electronically commutated motors (ECMs) also require motor control electronics, usually incorporated into the motor body itself, to operate.

Q: What's the benefit of having a greater number of poles?
A: A higher number of rotor poles increases motor efficiency, and reduces torque ripple, noise, and vibration compared to traditional switch reluctance motors.

Q: Have power factor and/or harmonics been tested?
A: The Oak Ridge National Laboratory assessment did not measure harmonics or power factor. The manufacturer reports that they should be the same as for a commercial VFD. Optional filters are available from the manufacturer to meet more stringent harmonics requirements.

Q: What is the long-term maintenance performance?
A: The evaluation period was short; long-term maintenance performance was not evaluated. In general, the motor should require less maintenance because the bearings are permanently sealed and no lubrication is required. Because there are no currents induced in the rotor, the smart motor does not experience arcing across the bearings, which should eliminate the premature bearing failure that can be experienced with AC induction motors.