Variable Speed Drives
This course provides training on variable frequency drives (VFDs). It includes “hands-on” demonstrations for skills improvement and is specifically designed for maintenance technicians and others working in industrial plants or wherever variable speed control applications are found. It also provides great refresher training for experienced electricians and engineers.
Curriculum
1. VFD safety review
- Electrical hazards, lockout-tagout, personal protective equipment and insulated tools
2. Functions of VFD
- Motion control/motor speed, air flow/liquid flow/pressure control, eliminating the need for variable transmission or sheave, variable vanes or dampers on fans, variable valves on pumps
3. Benefits of using a VFD
- Energy savings, easier maintenance, enhanced system monitoring
4. Load types
- Constant torque–conveyors, positive displacement pumps, superchargers, variable torque– centrifugal fans or pumps, saws, routers, planers
5. VFD options
- Bypass—two or three contactor style, disconnect switch style, soft starter, fusing VFD or bypass protection, motor overload device, transient protection, auxiliary relays, powerline phase reversal detection
6. Installation of a VFD
- Environmental concerns, clearances, conduit entry
7. Customer connections
- Safety circuit, start/stop, jog, status indication, fault indication, remote speed reference, monitoring of motor parameters)
8. Wiring and grounding VFDs
- Induced signals, inductive, capacitive, incoming powerline wiring, motor (load) wiring, control wiring, proper grounding methods
9. Controlling a VFD
- Keypad controls, terminal strip control (automatic and manual),bus communication control, open loop control, manual operation, automatic operation, sensor-less flux vector, closed loop control, Pi loop configuration, sensor or transducer feedback, motor shaft encoder feedback
10. VFD setup, programming and troubleshooting
- The importance of monitoring the VFD, maintenance, considerations for a VFD, identifying and isolating a VFD problem from a motor problem, troubleshooting the most common VFD problems.