Products infomation

Thermal control unit for a heater

Single-phase Three-phase thyristor-control unit

TOYO Paracon XP series


Our "Heater temperature control technology" accumulated thought many years of experience is applicable in wide fields.

1. Wide variety of product lineup!

Eleven types with current rating of 20A to 600A are
available for each of single-phase and three-phase series
to meet diverse needs.

2. Sophisticated functions are available as option!

Current regulating / Voltage regulating / Power regulating
functions, heater breakage detection function, and
optional. The "Sheet-key setting unit" shows load status
such as current, voltage and power with 7-segment

3. More thorough standard equipment!

Various functions including current-limiting, over current
detection, fast-blow fuse, thyristor error detection which
were optional to old models are now included as standard
equipment. Moreover, error detection function and
anomalous power with 7-segment indication facilitate

4. Strong, slim, compact structure!

Board mounting area ratio is improved : CT (Current
Transformer) and an optional PT (Potential Transformer)
can be contained in the compact body.

5. Sheet-key setting unit renders maintenance
unnecessary (option)

Load status of various function settings and optional
functions are displayed for more user-friendliness. Error
code corresponding with the detected error is detected
to facilitate maintenance.

Single-phase unit XP1 series

Three-phase unit XP3 series

How to Select Model Type

Typical Application

Steel industry

Used in a heater for heat-treating metal, etc.
As high capacity, special heaters that can withstand a high temperature are often used, phase control types are used.
Semiconductor industry

Used in constant temperature baths, etc. that require delicate temperature control.
Both phase control and zero-cross control types are frequently used.
Molding equipment industry

Used in heaters for injection molding equipment, etc. for controlling temperature.
Phase control types are mainly used.

Air conditioning industry

Used in air conditioning equipment including ones for clean room and operating room for controlling temperature and humidity.
Zero-cross control types are often used as general heater of nichrome is often used in places where equipment should receive minimum noise.
Food processing industry

"Paracon" works like a chef in controlling temperature to equalize the extent of baking bread, cookies, pizzas, etc.
Ceramic industry

Controlling technology of the "Paracon" is highly-esteemed in burning ceramics including IC chips using very high temperature (1500 to 1600 degrees Centigrade)
Painting industry

control function of the "Paracon" is adopted as inevitable system in improving quality when equal and even baking finishing is required.

TOYO Paracon has rich functions and works greatly in controlling temperature of heaters.

Standard function
Manual setting, soft start / shutdown, gain setting, operation command
input, setting change signal, current-limiting function, operation change
input, thyristor / load open error detection.

Error detection function
Frequency judgment error, fuse breakage error, temperature error,
thyristor / load open error, overcurrent error, heater breakage error,
instantaneous interruption error, communication error (option) Open
phase / negative phase for 3-phase type only.

Optional function
Current regulating function, voltage regulating function + current-
limiting function, power regulating function + current-limiting
function, heater breakage function, sheet-key setting unit (XP-SK).

Other functions
Error output / Heavy error · light error. Instantaneous interruption
detection function, overheat protection function, main circuit
"Sheet-key setting unit XP-SK" is available as an option for facilitating maintenance.
The equipment indicates function settings and load status data of various optional functions with lamps. "Error code" corresponding with the detected error is shown with 7-segment indication when a error is detected in current, voltage or power load to facilitate maintenance.

There are two control methods

Phase control
Power supplied to the load can be controlled continuously and the phase control is suitable for wide range of power control including that for general heater to a heater having large resistance change such as one in electric furnaces and air conditioners.

Behavior outline
Conduction time (firing angle) per cycle of AC power is controlled to
adjust AC power.
Output waveform chart
Zero-cross control (Cycle control)
The zero-cross control uses a firing system wherein a thyristor is turned on when the voltage of the AC power is zero and is suitable for controlling heaters close to instrumentation lines where noise should be minimized.

Behavior outline
AC power is adjusted by changing conduction cycle (On time) during one
period, which is cycles of AC power (in case of 50Hz and 2 seconds
Output waveform

* Zero-cross control is switched with external contact.

The application load of the Paracon is compatible with the following heaters.

General heater
General heater refers to heater with small resistance change caused by heater temperature such as nichrome or iron-chromium one. Standard units are optimal for controlling the load and optional functions can be added on request.
Precious metal heater
Precious metal heater refers to heater with very large resistance change of about ten times caused by temperature of heater such as pure metal heater including platinum, molybdenum, kanthal, or tungsten and nonmetal heater including molybdenum silicide. The current-limiting function [standard] and
current regulating function (optional) are optimal for controlling the load.
Silicone carbide heater
Silicone carbide heater refers to a heater whose resistance is changed greatly by heater temperature and electric resistance varies across the age due to wear of the heater. The current-limiting function (standard) and power regulating function (optional) are optimal for controlling the load.


Number of phase
single-phase / three phase
Rated current
20A to 600A (refer to selection table)
Input frequency
50 / 60Hz
Input voltage
100 / 110V, 200 / 220V, 400 / 440V 10%
Main circuit configuration (Module)
single-phase : thyristor + thyristor
Three-phase : thyristor + diode
Cooling method
single-phase XP1-020 - 150A self cooling XP1-200 - 600A fan cooling
three-phase XP3-020 - 100A self cooling XP3-150 - 600A fan cooling
Control method
phase control / zero-cross control
Applicable load
General heater, Precious metal heater, Silicon carbide heater (controllable with primary transformer)
Output adjustable range
0 to 98% or wider (with respect to power voltage)
Input characteristics
linearity 3% FS (output 10% to 90%)
Control power
external supply system (same power as the main circuit power)
Setting system
automatic / manual, two-position setting
Dielectric resistance
2000V 1 minute (at 200V system), 2500V 1 minute (at 400V system)
Insulation resistance
10MOhm or more with a DC500V megohmmeter
Operating temperature
0 to 50C
Storage temperature

-20 to 70C