Watlow Electric Microprocessor-Based SCR User Manual

P OW E R S E R I E S C O N T R O L L E R S

M i c ro p ro c e s s o r- B a s e d
SCR Power Contro l l e r
Designed fo r
Application Flex i b i l i t y

Watlow has manufactured solid state power controllers for
over thirty years. Watlow’s POWER SERIES represents the
latest in SCR power controller technology.This microproces­sor-based product offers features and application flexibility
unmatched by any other SCR power controller on the market
today.

Capabilities of Watlow’s POWER SERIES controllers include
single-phase and three-phase models from 65 to 250 amps.
Field configurable phase angle or zero cross firing improves
application flexibility on site where you need it.The 50/60Hz
independent operation allows utilization almost everywhere
in the world without special calibration considerations. Serial
communication utilizing Modbus™protocol provides remote
control setup and monitoring of load status from a nearby
computer station or control room.

On-board semiconductor fusing improves reliability by
protecting the SCRs from heater short circuits. Plus,
on-board heater bakeout and control diagnostics can help
eliminate initial start up problems. All these benefits are in a
touch-safe package that can be quickly and easily mounted
in your control cabinet.

Watlow’s POWER SERIES controllers are UL®and C-UL
recognized, so users can be assured that the controllers
meet world safety and operational standards.

®

Features and Benefits

Microprocessor-based technology

• Extremely versatile and field configurable

Snap-fit on a pre-mounted plate

• Simplifies installation

Models 65 through 250 amp ratings

• Handles a wide range of loads

Adjustable soft start

• Provides application flexibility

Heater and control diagnostics capability

• Monitors actual heater and controller performance

Electrically touch-safe package

• Enhances safety for installer and users

Serial communications with Modbus™RTU protocol

• Provides computer control and/or monitoring

Multizone capability

• Increases application flexibility and reduces panel space

UL®and C-UL®are registered trademarks of the Underwriter’s Laboratories, Inc.
Modbus™ is a trademark of Schneider Automation Inc.

1241 Bundy Boulevard
Winona, Minnesota 55987-5580 USA
Phone: [phone]
Fax: [phone]
Internet: www.watlow.com
e-mail: [e-mail]

© 2003 Watlow Electric Manufacturing Company Printed in the USA on Recycled Paper, 15% Postconsumer Waste

WIN-PS-0403

Specifications

Power Bases

• Single phase, (2 SCRs)

• 3 phase, 2 leg control, (4 SCRs)
Resistive load only, zero cross firing only

• 3 phase, 3 leg control, (6 SCRs)

• 3 phase, 3 leg control, (6 SCRs) for 4-wire wye loads

• Multizone, two and three single-phase zones

Output Control Options

• Zero cross contactor, VÎ(dc) input

• Zero cross control, fixed time base

• Time base one or four seconds with digital programmer

• Zero cross control, variable time base

• Phase angle control and phase angle control with current limit
(not for 3-phase, 2-leg models)

• Soft start factory default four seconds upon power-up, and

adjustable from 0.0 to 120 seconds

• Soft start upon input signal change, output rate of change

adjustable to limit max rate of change from 0.1 to 100 percent
per 0.1 second. Factory default 10 percent

• Current transformer included when required

• Line voltage compensated (variable time base and phase angle
controllers only)

• Standby or non-operational mode

Output Voltage and Current Rating

• 24 to 120VÅ(ac) (+10 percent, -15 percent)

• 200 to 480VÅ(ac) (+10 percent, -15 percent)

• 200 to 600VÅ (ac) (+10 percent, -15 percent)

• 65 through 250 amps per pole, model dependent; see Output
Amperage Chart and Rating Curves

• Minimum load 1 amp rms ac

• Maximum leakage current 5mA

Alarms

• Single alarm relay

• Latching or non-latching

• Separate high and low values

• Alarm silencing (inhibit) on power up for alarm

• Alarm indication LEDs, shorted SCR, open heater, fuse

• Electromechanical relay, form C contact, software
configurable

• Minimum load current 10mA @ 5VÎ(dc)

• Rated resistive loads: 3 amps @ 250VÅ(ac) or 30VÎ(dc)

max., inductive load rating 1.5 amps with a power factor
≥ 0.4 without contact suppression

Heater Bakeout

• For single-phase (phase to neutral) and 3-phase 6 SCR
models only (not for 3-phase, 2-leg models)

• Soft start with over current trip, runs until programmed bakeout
time expires, then goes burst or phase angle firing. Factory
default of 24 hours

• Adjustable 0 - 9999 minutes with over current trip

• Internal current transformer included

Command Signal Input
Analog

• Field selectable linear voltage and current of low and high
points within 0-20mA and 0-10VÎ(dc)

• Manual control input through front panel

• Factory default 4-20mA input

• Voltage input impedance 11kW nominal

• Current input impedance 100W nominal

Digital

• On-board digital programmer/display and optional serial
communications

Retransmit

• Field selectable and scalable within 0-20mA,
800W maximum or 0-10VÎ(dc), load, 1KW minimum load.
The default is 4-20mA

• Resolution:
mA ranges = ±5µA
VÎ(dc) = ranges 2.5mV nominal

• Calibration accuracy:
mA ranges = ±20µA
VÎ(dc) ranges = 10mV nominal

• Temperature stability: 100ppm°C

Digital Programmer/Display and Communications
Capabilities

• Programming functions

• Adjust input and output control type, alarms and soft start,

heater bakeout and current limit prompts

• Monitoring functions

• Display input and output values along with actual

output current

• Data retention of digital programmer/display upon power failure
via nonvolatile memory

Serial Communications

• RS-232 for single drop control

• EIA-485 for single or multidrop control

• 32 units maximum can be connected.With additional

485 repeater hardware, up to 247 units may be connected

• Isolated

• Modbus™RTU protocol

• 1200, 2400, 4800, 9600, 19200 baud rates

Controller Power Supply

• Universal line voltage input range 100 to 240VÅ(ac)
(+10 percent, -15 percent) at 55VA max

• 50/60Hz ± 5 percent line frequency independent

• Controller line voltage for electronic power supply can be run
on separate line voltage

Natural Convection and Fan Cooled Models

• Cabinet venting may be required

• See Amperage chart on the back page for all models.

Power Dissipation (Watts)

• Approximately 1.25 watts/amp per controlled leg

Isolation

• Command signal to load and line/load to ground
2200VÅ(ac) minimum

• On-board semiconductor fuses provide SCR protection

Mounting

• Mounts on a removable subplate

• Heat sink fins must be mounted in vertical orientation

High Current Terminals

• Touch safe

• 10 mm (3⁄8in.) Allen head compression terminals will accept
#6 AWG to 350 MCM wire. Allen wrench adapter (included) for
10 mm (3⁄8in.) socket, 6 point only

• Torque to 180 in.-lbs (20.3 Nm)

• Wire strip to 30 mm (11⁄8 in.)

Controller Terminals

• Touch safe

• 2.5 mm (1⁄8 in.) blade screwdriver, accepts 12-22 AWG or
2 No. 22-18 AWG wires

• Torque to 8 in.-lbs (0.9 Nm)

• Wire strip to 6 mm (0.24 in.)

Operating Environment

• 50°C (122°F) base rating

• 0 to 60°C (32 to 140°F) fan cooled

• 0 to 65°C (32 to 149°F) natural convection cooled

• 0 to 90 percent RH, non-condensing

• Meets EN50178, Pollution degree three

Storage Temperature

• -40 to 85°C (-40 to 185°F)

Shipping Weight

• 10.3 kg (23 lbs)

Agency Approvals

• UL®508 listed, File #E73741, Vol. three, Sec.two

• C-UL®listed to C22.2 NO. 14

• VDE EN 50178 License 115054

• CE 89/336/EEC (EN61326), Class A with filter,
CE 73/23/EEC (EN50178)

Modbus™ is a trademark of Schneider Automation, Inc.