DG 3802
DG3802

Thermistor Motor Protection Relay DG 3802

Reliable Protection against Over-Temperature with Thermistor/ PTC Resistor Sensor and Bimetal Breakers

The Thermistor Motor Protection Relay DG 3802 protects motors und machines against over-temperature caused by heavy starting duties, braking, under-voltage, over-voltage and high switching frequencies.

Reliable overtemperature protection
Up to 6 thermistors or bimetal switches, wire break detection in the sensor input
Fault message in closed-circuit operation
2 output relays not activated in the event of fault, restart via auto-reset
Status indication by LED
Easy monitoring and switching point adjustment
Protective Separation acc. to EN 61010
Protects service personnel and downstream devices against impermissibly high voltage
High reliability and noise immunity
No microprocessor, no integrated software
Extremely slim design
12.5 mm slim housing for a simple and space saving DIN rail mounting
5 Years Warranty
Defects occurring within 5 years from delivery date shall be remedied free of charge at our plant

Additional applications include monitoring the temperature of transformers, pumps, centrifuges, motor bearings, gearboxes, oil and coolants and the avoidance of thermal overload in the event of impeded cooling and high ambient temperatures.

The temperature is monitored directly at the winding using thermistors or bimetal switches. Up to 6 sensors can be connected in series. When a certain resistance is reached, the output relays switch off. Restarting takes place after cooling down via auto-reset.

The motor protection relay works with open circuit operation and also detects broken wire in the sensor circuit. The monitoring state is indicated by a yellow LED. The relay changeover-contact switches high power loads up to 6 A.

The Protective Separation and the 24 V DC power supply makes the DG 3802 universally applicable for all measurement and industrial applications, as well as for building automation.

Product line

Product line DG 3802
Device	Order No.
Thermistor Motor Protection Relay	DG 3802

Downloads / Links

Data sheet

User Instructions (221.8 KiB)

Additional Documents

CAD data (839.9 KiB)

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Technical Data

Input

Monitoring sensors	Thermistor/ PTC Resistor Sensor and Thermical Bimetal Switches (breakers, e.g. Klixon)
Monitoring function	Over-temperature protection in open circuit operation, restart via auto-reset
Number of sensors	1 … 6 pcs
Sensor load	≤ 1 mA / 1 V / 1 mW
Threshold value	≥ 3 kΩ (relays drop out)
Release value	≤ 1.7 kΩ (relays pick up)

Output

Contact type	2 isolated changeover relays (SPDT), synchronous switching
Switching capability AC max.	250 V / 6 A, 1500 VA
Switching capability DC max.	250 V / 0.2 A, 115 V / 0.3 A, 30 V / 6 A
Recommended minimum load	300 mW / 5 V / 5 mA
Status indication	yellow LED
Response time	< 50 ms

General Data

Switch error	< 5 %
Temperature coefficient 1)	< 0.03 %/K
Test voltage	4 kV AC, 50 Hz, 1 min. input against power supply against both switching outputs 3 kV AC, 50 Hz, 1 min. switching output 1 against switching output 2
Working voltage (Basic Insulation) 2)	1000 V AC/DC for overvoltage category II and 600 V AC/DC for overvoltage category III according to DIN EN 61010 with pollution degree 2 between input, power supply and both switching outputs. Furthermore 300 V AC/DC between output 1 and output 2.
Protection against electrical shock 2)	Protective separation according to DIN EN 61140 by reinforced insulation according to DIN EN 61010 up to 600 V AC/DC at overvoltage category II and 300 V AC/DC at overvoltage category III at pollution degree 2 between input, power supply and both switching outputs. Furthermore 300 V AC/DC between output 1 and output 2.
Power supply	24 V DC,  15 %, approx. 0.7 W
Ambient temperature	Operation Transport and storage	–20 °C to +60 °C (-4 to +140 °F) –35 °C to +85 °C (-31 to +185 °F)
EMC 3)	EN 61326 -1
MTBF (acc. to EN 61709 / SN 29500)	361.5 years (Tamb. 40 °C, FIT 315.5)
Construction	12.5 mm (0.5") housing, protection class IP 20, mounting on 35 mm DIN rail acc. to EN 60715
Connection	Captive plus-minus clamp screws, Wire cross-section max. 2.5 mm² / AWG 14 Stripped length 6 … 8 mm / 0.28 in, Screw terminal torque 0.8 Nm / 7 lbf in
Weight	70 g

Average TC related to full scale value in specified operating temperature range, reference temperature 23 °C
For applications with high working voltages, ensure there is sufficient spacing or isolation from neighboring devices and protection against electric shocks
Minor deviations possible during interference