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HomeProducts Power Switching Watlow Solid State Power Controllers Watlow QPAC SCR Power Controller Watlow QPAC Power Controller

Watlow QPAC Power Controller

up to 1000 amps
Watlow QPAC Power Controller
The QPAC SERIES from Watlow® is a modular Silicon Controlled Rectifier (SCR) power controller with plug-in features for flexibility. Bases are rated from 150 to 1000 amperes in one-phase, three-phase, two leg and three-phase, three leg.

A variety of transformers from 120 to 575VAC along with 50/60Hz operation enable the QPAC to operate in applications anywhere. Plug-in control cards set the QPAC’s SCR firing modes; solid state contactor, burst firing (zero cross) or phase-angle models are available with a wide variety of options. This power controller includes 200KA short circuit current rating (SCCR) and high speed fuses to minimize damage in the event of a short circuit.


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Features
Specifications
Ordering information
Resources
Applications

Product Features

200KA short circuit current rating (SCCR)
  • Minimizes damage in the event of a short circuit
Modular power controller
  • Unit base can be fitted with a variety of plug-in transformers and control cards
Available in 150 to 1000 ampere ratings
  • Handles large or small loads
Available in solid state contactor, burst firing (zero cross) or phase-angle fired mode
  • Meets most application requirements
Rugged design for 122°F (50°C) ambient operation
  • Full rating of the power controller can be used in industrial applications
Semiconductor fuses and snubber protection included
  • Protects the SCR from voltage or current surges or spikes
Open heater or shorted SCR detector option
  • Diagnostic capabilities
UL® 508 listed and C-UL® up to 1000 amperes
  • For applications requiring agency approvals

Product Specifications

Operation Modular controller base with plug-in card and transformer:
  • Plug-in control cards
  • Solid state contactor, dc input
  • Burst fire control, fixed or variable time base
  • Phase-angle fire control
  • Phase-angle control with soft start and current limiting
  • Plug-in transformers (50/60Hz)
  • 120, 208, 240, 380, 415, 480, 575VAC operation
Power bases:
  • 1-phase (Q01), 1 pair of SCRs
  • 3-phase (Q32), 2 leg control, 2 pair SCRs
  • Resistive load only, burst firing only
  • 3-phase (Q33), 3 pair hybrid SCRs/diodes
  • Recommended for phase-angle only with balanced load
Agency Approvals:
  • UL® 508 and C-UL® listed, 150 to 300A all configurations, File #E73741
  • UL® 508 and C-UL® listed, 400 to 1,000A on Q01 and Q32, up to 480VAC
Control Card Inputs:
  • (CD) Solid state contactor, dc input
  • On, 4-32VDC; off, 0.5VDC
  • Built-in noise reduction network
  • (BF) Burst firing control fixed time base
  • Process input factory set @ 4-20mA DC
  • Input impedance 250Ω (clip resistor for 5kΩ impedance voltage input), or manual control input
  • Time base 4 seconds (clip resistor for 1 sec)
  • (BV) Burst firing control, variable time base
  • Process input factory set @ 4-20mA DC
  • Input impedance 250Ω (clip resistor for 5kΩ impedance voltage input), or manual control input. Requires an accessory bias and gain card to calibrate for 0-5VDC input
  • (AF) Phase-angle control
  • Process input factory set @ 4-20mA DC
  • Input impedance 250Ω (clip resistor for 5kΩ impedance voltage input), or manual control input
  • Soft start approximately 6 seconds upon power-up, 1 second upon set point change
  • (AL) Phase-angle control with current limit
  • Process input factory set @ 4-20mA DC
  • Input impedance 250Ω (clip resistor for 5kΩ impedance voltage input), or manual control input
  • Soft start approximately 10 seconds upon power-up, 1 to 2 seconds upon set point change
  • Current transformer included
Open Heater/Shorted SCR Detector:
  • Zero cross/burst fire models only
  • Triac output
  • 24 to 240VAC, 300mA @ 77°F (25°C), 125mA @ 176°F (80°C)
  • Energizes on alarm
  • Holding current 200μA min.
  • Latching current 5mA typical
Outputs:
  • 120 through 575VAC
  • 1, 2 or 3 pole
  • 150 to 1000A per pole
  • SCCR, 200KA with original equipment specified semiconductor fusing
Line Voltage / Power:
  • 50/60Hz ac line frequency, Q32 and Q33 models are 50/60Hz calibration dependent
  • Voltage: ±10%, 120, 208, 240, 277, 380, 415, 480, 575VAC
Line Voltage Compensation:
10% Δ in line, 2% Δ in load in the 30 to 70% power region (AF, AL and BV)
Power Dissipation (Watts):
1.5 W/A per controlled leg
Isolation:
Command signal to load 1250VAC min.
Linearity:
2%, 30 to 70% power region (All units except CD)
Off-State Leakage Current:
20mA @ 480VAC
SCR Protection:
  • Semiconductor fuses provided dv/dt 200V/μsec min.
  • MOV1 and RC snubber network standard
  • (Q32) 3rd leg fuse kit may be used, but not required, with 3-phase, 2 leg models
Mounting:
Heat sink fins must be mounted in vertical orientation
Operating Environment:
  • 32 to 122°F (0 to 50°C)
  • 0 to 90% RH, non-condensing
  • 2,000 meters altitude
Storage Temperature:
-40 to 185°F (-40 to 85°C)
Options:
  • Manual Control Kit for process input cards (1kΩ potentiometer) #08-5362
  • 240VAC and 120VAC cooling fans

Ordering information

Resources

Literature

QPAC (SCR) Datasheet