HP Type K02, Class SMF Solid-State Reduced Voltage Starters, Shorted SCRa, Pump Stopa, Phase Loss

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AC Controls

Solid-State Reduced Voltage Starters

General

Operation

The solid state motor controller uses sili- con controlled rectifiers (SCR’s) to control the voltage to the motor windings. Each SCR acts as a switch that can be turned on with any electronic trigger signal at any point on the voltage waveform and turns off when the current waveform crosses zero. Two SCR’s are used in a back-to-back arrangement in each phase to allow alternating current to pass to the motor.

Shorted SCRa

If one or more shorted SCRs are detect- ed, the starter will not energize. A fault LED will light and if provided with a shunt trip, the main circuit breaker will trip.

Pump Stopa

This option eliminates water hammer in pumping systems, by giving a controlled decel to the motor voltage. This process allows for smooth pressure reduction and quiet check valve operation.

Phase Loss

The controller will trip off the line if one or more phases is lost.

Class 70 / 71

Siemens-Furnas Class 70 / 71 combines Digital Signal Processor control and sili- con controlled rectifier (SCR) technolo- gies to provide optimum AC induction motor starting and operation. It provides soft start, energy savings,* soft stop,* and added protective features.

The basic controller consists of electronic circuit boards linked via flat cable connec- tors. The main functions of the basic assembly are to monitor the operating parameters of the controller and to con- trol the firing sequence of the SCR’s. The power module located below the basic controller controls power to the motor. The incoming and motor load connections are made to terminal blocks located on the top and bottom of the power module.

The starters are available either as NEMA Type 1, 12, or 4 enclosures. Units are supplied with solid-state overload relays as complete starters, or as combination starters with fusible, non-fusible discon- nect, or thermal magnetic circuit breakers with or without shunt trip features. Additional options are also available.

The Class 70 / 71 is designed to operate 3 phase AC induction motors at 208 to 575 volts and 6.1 to 960 amperes at 50 or 60 Hertz.

aAvailable on 2000+ Starter

3-Phase Control Configuration

When SCR triggering is delayed, the volt- age to the load is reduced. This phase- controlled operation provides soft starting with stepless acceleration. Once the motor is running, voltage reduction can improve the motor’s operating point at partial load, saving energy and lowering the reactive current.

3RW2 Phase Control

15

AC Controls

CSI Section 16160

Siemens Electrical Products and Systems

307

 

Specification Guide

 

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Contents Manual Starters and Switches Typical Wiring DiagramsGeneral AC Controls Horsepower Ratings Manual Starters and Switches FeaturesClass SMF Heater Elements Dimensions General Purpose Flush MountingTwo Unit Devices Nema Type 1 General Purpose Enclosure General Purpose Flush Mounting for Two Unit DevicesManual Motor Starter Switches Dimension / Wiring DiagramsGeneral / Dimensions 3VU13 Enclosure DimensionsTechnical Data Manual Motor Starter ProtectorGeneral / Wiring Diagrams Manual Motor Starters and ContactorsClass 11 Manual Motor Starters Motor Starters Magnetic Contactors ApplicationsCoil Data 14 Reference LiteratureLighting and Heating Contactors 21 2-12 Pole Dimensions Wiring Diagrams TypicalCompact Magnetic Contactors Lighting 21WE 2-12 PoleCLM Contactors 300 and 400 Amperes, 2- and 3-Pole Combination Lighting and Heating Features DescriptionMagnetic Latch Operation Ballast LoadDimensions Combination Starters Nema SizesKey Features 27 Contactor Technical DataContactors Non-Reversing Key Features Cont’d Magnetic Motor Starters Full Voltage Non ReversingStarters Magnetic Motor Starters-Full Voltage Non Reversing Auxiliary EquipmentSize 0 through Dimensions / Wiring Diagrams Contactor DimensionsPole Single Phase Magnetic Contactors Size Sizes 2-31/2 Pole 3 Phase Magnetic Contactors Size 4 1/ 2Enclosure Dimensions Enclosures303 Full Voltage, Non-Reversing Starters Nema Sizes RatingsTorque Characteristics 33 3-Phase Multi-Speed StarterMulti-Speed Starters Nema Sizes Combination Multi-Speed StarterAuto Transformer Starter Wye Delta StarterPart Winding Starter OperationPhase Loss Solid-State Reduced Voltage StartersShorted SCRa Pump Stopa36 Solid-State Reduced Voltage Starters Pilot Device Units and Indicator Lights Type 3SBO Pilot Device UnitsEnclosed Pilot Device Stations Enclosed Pilot Device StationsGuide Form Specifications SpecificationsReduced Voltage Autotransformer Starters Multi-Speed StartersReduced Voltage Wye Delta Starters Reduced Voltage, Part Winding Starters
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