SCR Analog Power Controllers

Phase Angle Fired

Spang Power Electronics designs and manufactures a full line of single and three phase, phase angle fired SCR power controllers.

In phase angle control, the SCR is gated every cycle. Power control is accomplished by delaying SCR gating until some time after the voltage crosses zero. By varying this delay (measured in electrical degrees), the time the SCR is allowed to conduct is varied, as is the output power.

Phase angle control has the advantage of proportioning every cycle. This "subcycle" control allows voltage to be gradually applied to the load. When feeding the primary of a transformer (or other inductive load) this is very important. A phase angle fired unit can be gradually turned on, providing a soft start to eliminate transformer inrush.

Product Line Overview

The "B" Series
The "B" series power controller offers the widest variety of ratings, features and options. This series is available in ratings from 15 to 3000 amps. Options include voltage, current or watt limit, voltage, current or watt regulation, overcurrent shutdown and NEMA enclosures. The Spang "B" Series can also be equipped with special options such as pilot lights, meters, circuit breakers and water cooling.

The "C" Series

The "C’ series power controller is a smaller, lighter, more cost efficient unit which delivers peak performance under tough industrial conditions. This controller is a three phase unit which is available with ratings from 40 to 350 amps. Options include current limit and voltage regulation. NEMA 1 enclosures are also available.

The 751 Series
This single phase power control unit offers numerous standard features in a compact package. This controller provides complete user customizing capabilities without rewiring or adding additional components. The user may choose four types of limiting (current, voltage, power or open) and four types of regulation (current, voltage, power or open). In addition, the 751 Series has built-in current, voltage and watt transducers. Available in ratings from 50 to 175 amps.

The 650 Series
The 650 Series units are definite purpose controllers which offer economical power control in a compact package. Options include current limit and/or voltage regulation and are available in ratings from 15 to 110 amps.

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