Type A PTC temperature sensor

If a Type A temperature sensor is connected to a Type A evaluation unit, compliance with the operating temperatures is assured (on pick-up and reset) according to IEC 60947-8.

Characteristic curve of the 3RN1 evaluation unit

The characteristic curves of the Type A temperature sensors are described in IEC 60947-8, DIN 44081 and EN 44082 standards.

Use in areas subject to explosion hazard for gases

All devices are approved for Equipment Group II, Category (2) in Area "G" (areas that contain explosive gases, vapor, spray and air mixtures).

Compliance with Directive 94/9 EC Appendix II is confirmed with PTB 01 ATEX X3218 ex II (2) G. The safety devices must be selected with suitable settings for the safe operation of motors of the "Increased safety" (EEx e) and "Flameproof enclosure" (EEx d) types of protection and are used outside the area subject to explosion hazard.

PTB 01 ATEX 3218 ex II (2) G

The increased danger in areas subject to explosion hazard calls for careful compliance with the operating manual, the safety and commissioning instructions and the standard (EN 60079-14/VDE 0165) for electronic equipment in areas subject to gas explosion hazards.

A risk analysis must be performed for the complete plant or machine. If this risk analysis results in a minimal potential for danger (Safety Category 1), all 3RN1 TMS evaluation units can be implemented taking into account the safety notes. In the case of plants or machines with a high potential risk, device versions with integrated short-circuit detection in the sensor circuit are necessary.

Use in areas subject to explosion hazard for dust

PTB 01 ATEX 3218 ex II (2) GD

3RN1011-.B/-.G, 3RN1012-.B/-.G and 3RN1013-...0 evaluation units can be used as protective devices for motors in areas subject to gas explosion hazard for protection against impermissible overheating due to overload. If the ATEX identification has the extension "D:=Dust", these units can also be used as protective devices for motors in areas subject to dust explosion hazard (IEC 61241-14).

Additional information is provided in the EC type test certificate which can be obtained from the Internet. The units comply with the requirements of the following classes:

The measuring circuit cables must be routed as separate control cables. It is not permitted to use cores from the supply line of the motor or any other main supply cables. If extreme inductive or capacitive interference is expected as a result of power lines routed in parallel, shielded control cables must be used.

Cable routing

Maximum cable length for sensor circuit cables

¹⁾ Short-circuits in the sensor circuit are detected up to this maximum cable length.

Notes:

Tripping of the thermistor motor protection relay even in combination with a converter must directly result in disconnection. This must be implemented with circuitry.

Mounting and installation must only be performed by qualified personnel who observe the applicable regulations! For mounting, use the mounting instructions with the Article No.: 3ZX1012-0RN10-1AA1.

The 3RN10 is not intended for installation in hazardous areas. For installation in areas subject to explosion hazards, the 3RN10 must be enclosed in a flameproof casing.

For evaluation units with a 24 V AC/DC control voltage, electrical separation must be secured with a battery network or a safety transformer.

When evaluation units with Auto RESET function are used, resetting is performed automatically after the cooling time has expired. It must be ensured by means of an external interlock (latching with a separate ON and OFF button) that the machine to be monitored does not start up again spontaneously.

Units with the "Auto RESET" function must not be used in applications in which the unexpected restart can lead to personal injury or property damage. In the case of evaluation units without short-circuit detection, during commissioning or after modifications or maintenance work (assembly, disassembly) on the equipment, the sensor resistance must be measured using a suitable measuring device. For resistance values of < 50 О© the sensor circuit must be checked for a short-circuit.

If 3RN1000 units are used to protect EEx e motors, it is advisable to monitor the control voltage separately because there is no "Ready" LED to indicate that this voltage is present. If 3RN1013-.BW01 unit are used to protect EEx e motors, separate monitoring of the control voltage is recommended because the switching state of the auxiliary contacts does not change if the control voltage fails (use of a bistable relay is recommended).

Before commissioning, the effectiveness of the protection function must be checked.

Operating principle

The 3RN1 evaluation units operate in accordance with the closed-circuit principle and therefore monitor themselves for open circuit (except: warning output in the case of 3RN1022). A momentary voltage failure of less than 50 ms does not change the status of the auxiliary contacts. The 3RN1011, 3RN1012 and 3RN1013 units with 2 changeover contacts are also equipped with short-circuit detection in the sensor circuit. The unit will trip in the event of a short circuit in the sensor circuit (resistance in sensor circuit < 20 О©).

All evaluation units (except for 24 V AC/DC) feature electrical separation between the control circuit and the sensor circuit.

For devices with the "Manual RESET" function, the test function can be activated and a trip simulated by pressing the blue Test/RESET button for > 2 seconds.

3RN1000 compact evaluation unit

The compact unit is equipped with a red LED (TRIPPED) for the tripped indicator and a changeover contact.

After the unit has tripped, it is automatically reset once the thermistors have cooled down. The root of the changeover contact is connected to the control voltage (95 is connected to terminal A1).

This unit is particularly suitable in circuits in which the control circuit and signaling circuit have the same potential, e.g. in local control cabinets.

3RN1010, 3RN1011, 3RN1012, 3RN1013 standard evaluation units

The standard units are equipped with two LEDs (READY and TRIPPED) for an operating and tripped display and are available with either 1 NO + 1 NC or with 2 CO contacts. They are available depending on the version with Auto RESET (3RN1010), Manual/Remote RESET (3RN1011) or Manual/Auto and Remote RESET (3RN1012 and 3RN1013). Remote RESET can be achieved by connecting an external pushbutton with a normally open function to terminals Y1 and Y2. If terminals Y1 and Y2 are bridged, tripping will be followed by an Auto RESET.
The 3RN1011, 3RN1012 and 3RN1013 units with 2 CO contacts also have short-circuit monitoring in the sensor circuit.
The 3RN1012 and the 3RN1013 are non-volatile. This means that even if the control supply voltage fails, a trip preceding it will be saved.
In the case of the 3RN1013 evaluation unit, tripping due to a short circuit in the sensor circuit will be indicated by a flashing red LED. The monostable version also indicates open circuit in the sensor circuit by flashing of the red LED.

3RN1022 "Warning and disconnection" evaluation units

Two sensor circuits can be connected to one 3RN1022 evaluation unit that acts on one output relay with 1 NO contact for warning and 1 CO contact for disconnection. Temperature sensors with different rated response temperatures TNF are used to implement the "Warning" and "Disconnection" functions. When the "Warning" sensor circuit responds, a yellow LED is lit and when the "Disconnection" circuit responds, a red LED is lit.

The sensor circuits have a different reset response and operating behavior:

• "Warning" (terminals 2T1, T2) only features Auto RESET and uses the open-circuit principle.
• "Disconnection" (terminals 1T1, T2) can be changed from Manual RESET to Auto RESET by linking terminals Y1 and Y2. Remote RESET is implemented by connecting an external pushbutton with a normally-open function.

3RN1062 multiple motor protection evaluation units

Up to 6 sensor circuits can be connected to the 3RN1062 evaluation unit, all of which act on one output relay. The simultaneous protection of several motors (up to 6) is an advantage for multi-motor drives (e.g. if one motor is overloaded, all the other motors of the drive will be shut down). Apart from the red LED "TRIPPED", which signals the switching state of the evaluation unit, an LED is assigned to each sensor circuit which indicates the sensor circuit that has responded during tripping. Unused sensor circuits must be short-circuited.

The reset response of the 3RN1062 evaluation units can be changed from Manual RESET to Auto RESET by linking terminals Y1 and Y2. Remote RESET is implemented by connecting an external pushbutton with a normally-open function.

Response of the evaluation units in the event of control voltage failure

Protective separation

All circuits (outputs, control circuits, sensors and RESET circuits) of the multifunction evaluation units 3RN1013-1BW10 and 3RN1013-1GW10 (wide voltage range, monostable output relay and screw connection) are safely isolated from each other up to a rated voltage of 300 V according to IEC 60947-1.

Function diagrams

3RN1000, 3RN1010 (Auto RESET)

3RN1011¹⁾

3RN1012/3RN1022/3RN1062 ¹⁾

3RN1013-.BW01

3RN1013-...00

3RN1022 only

¹⁾ For versions with 2 CO contacts and short-circuit detection in the sensor circuit, see function diagram 3RN1013.