Watlow VPAC-AT User Manual

VPAC-AT

Remote Mount Transformer

Data Sheet

General Description

The AT card (Watlow P/N 08-5422) provides a delayed
SCR turn ON, providing an infinitely variable voltage and
current from full OFF to full ON. The AT card can be
used on resistive, inductive, or Tungsten lamp loads. It
includes a 2-4 second soft start on power up, and a one
second soft start on input signal step change. The AT
also includes a missing half cycle detector to put it into
emergency shutdown (ESD), and retrigger the soft start.
A low signal on the ESD terminals puts the unit into
ESD. The input is factory set for 4-20mA into 250Ω. It
can be converted to a voltage input by removing R2 and
readjusting the bias and gain potentiometers for any volt­age from 0-3VÎ (dc) to 0-15VÎ (dc). Without R2, it is a
5K input impedance. See the illustration on the reverse
side.

AT card power supply requirements are 24VÅ (ac) cen­ter tap transformer secondary. Transformer primary
must be connected to the same line phase as the heater
load. For example, is the heater is powered by L1 and
L2, then the power transformer must also be connected
to L1 and L2. See the illustration on the reverse side.

Dimensions

Specifications

Input

• Process input factory set @ 4-20mA Î (dc)

• Input impedance 250Ω (clip resistor for 5KΩ voltage
input), or manual control input

• Soft start approximately 2-4 seconds upon power­up, 1 second upon set point change

Output

• Phase angle control

• TTL compatible (5V logic) at about 5mA @ 5V. Will
drive one industry standard 3-32VÎ (dc) input ran­dom fire SSR. For single phase only.

Line Voltage Power

• 50/60 Hz V~ (ac) line frequency

• Voltage ±10%, 120, 208, 240, 277, 380, 415, 480V~
(ac). Power transformer is supplied with the AT
card. When ordering, specify power supply voltage
and line frequency.

Line Voltage Compensation

• 10%∆ in line, 2%∆ in load in the 30% to 70% power
region.

Input to Output Linearity

• 2%, 30% to 70% power region

Operating Environment

• 32 to 122°F (0 to 50°C)

Storage Temperature

• -40 to 185°F (-40 to 85°C)

Options

• Manual control kit for voltage input cards (1KΩ
potentiometer) #08-5362. Includes dial, knob, 1KΩ
pot and wiring.

Ordering Information

• Watlow P/N 08-5422

(1274)

Watlow Controls

1241 Bundy Blvd., P.O. Box 5580

Phone: [phone], Fax: [phone]

0600-0028-0001 Rev D Made in the U.S.A.

August, 1999 Printed on Recycled Paper

(1275)

Winona, MN 55987-5580

10% Postconsumer Waste

Remote Mount Transformer

Wiring Diagram for VPAC-AT

Note:

The controls transformer must

be on the same phase as the

load. See wiring diagram. All

hot lines to the transformer

should be fused at 1 amp with

the proper line voltage.

For manual control, a 1KΩ

potentiometer may be connected

to the AT card input terminals.

Watlow offers a Manual Control

Kit, P/N 08-5362. Using this

potentiometer requires removing

the 5KΩ, R2 resistor for higher

impedance.

Bias and gain adjustment is

required when changing from 4-

20mA input to a manual control

input or a voltage input.