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Siemens 3RU2146-4KB1 — Overload Relays

Siemens 3RU2146-4KB1 SIRIUS Thermal Overload Relay, Size S3,

MPN3RU2146-4KB1
Active

Siemens SIRIUS thermal overload relay, Size S3, 3RU2146-4KB1, Trip Class 10, 37 kW at 400 V rated value, 65 A at 480 V rated value, screw-type terminals.

Source DocumentedChannel stated on listing & quote
Condition PhotosReal unit photos / video on request
WhatsApp AnswersFast human replies for machine-down parts
Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026

Specifications

3RU2146-4KB1 — Identification
ParameterValue
Product brand nameSIRIUS
Product designationthermal overload relay
Frame size (overload relay)S3
Combinable contactor sizesS3
Reference code (IEC 81346-2)F
3RU2146-4KB1 — Protection & Trip
ParameterValue
Overload current setting range57 ... 75 A
Trip classCLASS 10
Overload release typethermal
3RU2146-4KB1 — Electrical (main circuit)
ParameterValue
Rated operational current75 A
Poles (main circuit)3
Rated operating frequency50 ... 60 Hz
Rated insulation voltage (AC, pollution degree 3)1 000 V
Rated value (AC-3e), max.1 000 V
Rated surge withstand voltage8 kV
Main current circuitscrew-type terminals
Power loss at rated current (hot)18.9 W
Per pole6.3 W
3RU2146-4KB1 — Auxiliary contacts
ParameterValue
Auxiliary contacts: NO1
Auxiliary contacts: NC1
Auxiliary contacts: CO (changeover)0
Auxiliary switch short-circuit protection (required fuse)fuse gG: 6 A, quick: 10 A
Switching current at 24 V2 A
Switching current at 60 V0.3 A
Switching current at 110 V0.22 A
Switching current at 120 V3 A
Switching current at 125 V0.22 A
Switching current at 220 V0.11 A
Switching current at 230 V2 A
Switching current at 400 V1 A
3RU2146-4KB1 — Connection & Mounting
ParameterValue
Mounting / fastening methodstand-alone installation
Mounting positionany
Main-circuit connector arrangementTop and bottom
Auxiliary/control circuit connection typescrew-type terminals
Removable aux./control terminalNo
Conductor cross-section: solid2x (2.5 ... 16 mm²)
Conductor cross-section: solid or stranded2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Conductor cross-section: finely stranded with ferrule2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Conductor range (AWG), main contacts2x (10 ... 1/0), 1x (10 ... 2/0)
Conductor range (AWG), auxiliary contacts2x (20 ... 16), 2x (18 ... 14)
3RU2146-4KB1 — Environmental
ParameterValue
Operating temperature-40 ... +70 °C
Storage temperature-55 ... +80 °C
Transport temperature-55 ... +80 °C
Relative humidity, operating10 ... 95 %
Max. installation altitude2 000 m
3RU2146-4KB1 — Mechanical
ParameterValue
Width70 mm
Height120 mm
Depth140 mm

Product details

The 37 kW at 400 V rated value and 65 A at 480 V rated value define the maximum motor power and full-load current the relay can protect at those voltages; match these to your motor nameplate, not the contactor rating. The relay mounts standalone (fastening method: stand-alone installation) in any position, so panel integration is flexible — no forced orientation.

Key specs that decide the wiring and panel fit

Terminals are screw-type for the main current circuit, accepting solid conductors 2x (2.5... 16 mm²) and stranded 2x (6... 16 mm²), 2x (10... 50 mm²), or 1x (10... 70 mm²). The screwdriver drive is a 4 mm hexagon socket — no Phillips or slotted head, so have the correct bit on hand. Auxiliary contacts are integrated, rated at 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V. Temperature compensation is active from -40 to +60 °C, with operating range -40 to +70 °C. During operation, the relay dissipates 6.3 W per pole.

What the Note for message Tripped means

The evidence lists a Note for message Tripped. This is the diagnostic signal the relay sends when it has operated — a tripped-state indication that can be wired into a PLC or control system to trigger an alarm or shutdown sequence. It is not a fault code; it is a binary status output that confirms the relay has opened the motor circuit due to overload or phase loss.

Frequently asked questions

Who supplies 3RU2146-4KB1 and how is it quoted?

It is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at the time of quote.

What is the closest functional second-source to 3RU2146-4KB1?

The 3RU2116-1FC1 is a SIRIUS thermal overload relay but in a smaller Size S2 form factor. It will not drop into a panel wired for the S3 3RU2146-4KB1 without rewiring and a different mounting footprint. The 3RU2146-4KB1 is the larger S3 frame for higher current ratings.

What is the Note for message Tripped on this relay?

It is a diagnostic signal indicating the relay has tripped due to overload or phase loss — a binary status output for a PLC or alarm circuit.

What is the depth of 3RU2146-4KB1?

The depth is 140 mm, with a width of 70 mm and height of 120 mm, fitting the standard S3 overload relay footprint.

Will 3RU2146-4KB1 drop into a panel specified around 3RU2116-1FC1?

No. The 3RU2146-4KB1 is Size S3 (70 mm wide, 140 mm deep) while the 3RU2116-1FC1 is Size S2. The mounting hole pattern and DIN-rail footprint differ, and the terminal capacity is larger on the S3. Rewiring and re-drilling the panel would be required.

MPN
3RU2146-4KB1