Installation and Wiring Instructions for Dry-Type Transformer Temperature Controllers

• mounting position: The thermostat is flush-mounted on the transformer housing panel at a height that allows for easy operation and reading. The panel cutout dimensions are determined by the thermostat model.
• PT100 Wiring: The three-wire connection is the most common method for connecting PT100 sensors, with two wires serving as current sources and one as a voltage measurement lead. This effectively compensates for the impact of lead resistance on measurement accuracy.
• Fan Control Wiring: The fan control contacts of the thermostat are connected in series with the fan's power circuit. When the winding temperature reaches the fan start setpoint, the contacts close to start the fan; when the temperature drops to the stop setpoint, the contacts open.

1. Wiring Guidelines

1.1 Power Connection— Thermostats typically operate on a 220 V AC power supply. The power cord should be connected to a separate control power circuit to avoid sharing the circuit with the main circuit. Before wiring, verify that the supply voltage matches the thermostat’s rated voltage.

1.2 Sensor Wiring——One PT100 platinum resistance thermometer is installed per phase, embedded at the ends of the A, B, and C low-voltage windings, respectively. The sensor leads are routed along the internal cable ducts of the transformer and connected to the corresponding terminals on the temperature controller according to the markings.

1.3 Alarm/Trip Outputs— Connect the alarm and trip contacts to the alarm and circuit breaker trip circuits, respectively. When wiring, ensure that the contact type (normally open/normally closed) matches the control circuit requirements and that the contact rating meets the load requirements.

2. Frequently Asked Questions FAQ

2.1 Q: What should I do if the PT100 sensor wire breaks?

A: If the break occurs outside the transformer, the wiring can be reconnected; if the break occurs inside the winding, the sensor generally needs to be replaced. During installation, ensure that the sensor lead is protected from mechanical damage.

2.2 Q: How do I troubleshoot a thermostat that shows no display after powering on?

A: First, check that the power connections are secure and that the voltage matches the rated value. If the power supply is working but there is no display, the internal power module may be faulty; contact the manufacturer for repairs.

2.3 Q: Why isn’t the fan starting even though the temperature has reached the set point?

Answer: Check whether the fan control contacts are outputting a signal, whether the fan’s power supply is functioning properly, and whether the fan itself is malfunctioning. Use a multimeter to measure the fan output terminals on the thermostat to determine whether the issue lies with the contacts or the fan.

Disclaimer: The content of this article is for technical exchanges and reference only, and does not constitute any form of procurement commitment or contract offer. Product technical parameters, configuration programs and prices are subject to the actual signed contracts and technical agreements.

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