#218 - Schneider Basics on Motor plates, DOL, Soft-Starter and ATV

Motor Plate:

DOL: - High starting current (up to 7x), high starting torque (up to 2.5x). - Compact and economical. - No speed control, no energy saving.

Star-Delta: - Low starting current (up to 2.3x), low starting torque (up to 0.8x). - Requires connection to 6x motor terminals and extra parts

Soft-Starter: - Voltage ramp limited through thyristors. - Low starting current (up to 2-5x), low starting torque (up to 1x). - No speed control, no energy saving. - Can easily replace a contactor (DOL) in an existing installation that has already a short-circuit and overload protection. - Both acceleration and deceleration can be controlled.

ATV VFD 6xx-9xx:

Common motor applications:

- Variable Torque. Torque is proportional to the square of the Speed: Centrifugal pumps, Fans, Blowers, HVAC, Ventilation, Air Compressors, Conveyors with varying load (warehouse).

Flow is proportional to the Speed. Pressure is proportional to the Speed squared.

Power is proportional to the Speed cubed.

- Constant Torque. Torque is constant whichever Speed: Conveyors, Material Handling, Hoist, Milling/Lathes, Mixers/Agitators, Positive displacement pumps.

- Duty (Over-load) in function of the application: Normal Duty (ND - up to 110% OL) vs. Heavy Duty (HD - up to 150% OL).

- Boost: e.g. Compressor, Rock crusher.

- Acceleration / Deceleration ramps: S-ramp > Elevator, U-ramp > Pump. Skip frequencies can be an option to avoid resonance frequencies.