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.

Package Style C Dimensions

Mounting Plate Dimensions

POWER SERIES Front View

POWER SERIES Top View

354 mm

(14.0 in.)

200 mm
(7.9 in.)

Mounting Holes (4)

7 mm

(0.27 in.)

Key Slots

102 mm

(4.00 in.)

151 mm

(5.93 in.)

Release Tab

178 mm

(7.00 in.)

25 mm

(0.97 in.)

39 mm
(1.53 in.)

191 mm

(7.5 in.)

POWER SERIES Features

Ordering Information

POWER SERIES P C _ _ - _ _ _ _ - _ _ _ _

Microprocessor-based,
solid state power controller

Package Style

C = 65 to 250 amps

Phase

1 = 1 phase
2 = 3-phase/2-leg control, (4 SCRs)
3 = 3-phase/3-leg control, (6 SCRs)
4 = 3-phase/4-wire, wye

connected load
8 = 2 single-phase zones
9 = 3 single-phase zones

Heater Diagnostics

0 = None
1 = Heater diagnostics (required for any

heater current monitoring or current

limiting).

Output Amperage Rating

(See amperage chart to the right)

Output Voltage Rating

A = 24 to 120V
B = 200 to 480V
C = 200 to 600V

Communications

0 = None
1 = EIA/TIA-232/485 communications,

opto-isolated (field selectable)

Feedback/Retransmit

0 = None
1 = Load current feedback (0-10V or 0-20mA scalable

retransmit output) (Must have heater

diagnostics selected)

Custom

00 = None
AA = No Watlow logo with agency approval marks
XX = Custom, consult factory for options

Your Authorized Watlow Distributor Is:

Single Phase Configuration

This configuration can be purchased with any or all the
features available on the POWER SERIES, based on
customer preference. It is intended for resistive heaters,
but can also be used on transformer connected loads in
the phase angle firing mode.

Three-Phase,Two Leg Configuration

This configuration is intended for zero cross firing only into
a stable resistive heater.Typically, a three-phase delta or
ungrounded wye connected heater is used and only two of
the three V~ line phases are switched.The third phase
is a direct connection through a bussbar on board the
POWER SERIES. Heater current monitoring and kVA options
are available via the heater diagnostics option.

Three-Phase,Three Leg Configuration

All POWER SERIES options are ava i l a ble with this
c o n fig u ra t i o n . It wo rks well with phase angle firing into a
t h r e e - p h a s e, three-wire wye or delta connected heater.In this
c o n fig u ration, the more common applications are tra n s fo rm e r
connected loads with heaters requiring a soft start and/or
current limiting.

The three-phase, four-wire configuration is intended for zero
cross firing into a three-phase grounded wye/star heater (This
is a separate hardware option, model number dependent.)

Single-Phase, Multizone Configuration

This configuration is available in two and three single-phase
zones and all the features of a single-phase unit are
available.(Note that there is only one alarm relay and all
zones in the controller must use the same control method.)

Heater Diagnostics

Heater diagnostics may include some or all of the
features that require heater current monitoring, depending
on the model selected. Heater current monitoring is only
available with heater diagnostics installed on the controller.
The features dependent on heater current monitoring are
heater bakeout, current limiting, heater kVA monitoring,
retransmit and heater monitoring alarms such as open heater,
heater out of tolerance, load balance and shorted SCR
detection/error.Heater diagnostics must also be installed
if you need phase angle control with current limit.

Amperage Chart—50˚C (122˚F)

Non-Fan Cooled

2 Zone and 3 Zone and

Single Phase 3 Phase, 2 Leg 3 Phase, 3 Leg

Code Amperage Code Amperage Code Amperage

N20 100A N20 80A N20 65A
N25 140A N25 105A N25 85A
N30 165A N30 120A N30 105A

Fan Cooled

Single Phase 3 Phase, 2 Leg 3 Phase, 3 Leg

Code Amperage Code Amperage Code Amperage

F20 125A F20 120A F20 90A
F25 200A F25 160A F25 140A
F30 250A F30 185A F30 155A

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Latin American Sales Office: Mexico, [phone]