SIEMENS 3RT1056-6AP36 Power Contactor

SIRIUS 3RT series 3-pole AC power contactor, Size S6, main circuit busbar connection, AC/DC 220~240V coil, built-in 2NO+2NC auxiliary contacts

1. Model Decoding

3RT1056-6AP36

3RT: SIRIUS power contactor series

10: Standard contactor (non-safety, non-reversing type)

56: Frame size S6, AC-3 400V 185A

6: Coil voltage 220…240V AC/DC

A: Main circuit busbar connection

P: Screw terminals for auxiliary contacts

36: Auxiliary contacts 2 Normally Open + 2 Normally Closed (2NO+2NC)

2. Core Electrical Specifications

3. Application Scope

On/off control of 3-phase motors such as fans, water pumps and compressors

Control cabinets, central air conditioning, industrial production lines and power cabinets

Can be matched with 3RU thermal overload relay for motor overload protection; 3RT19 surge suppressor for coil EMC interference suppression

4. Alternative Models
5. Domestic SIEMENS replacement: 3RT5056-6AP36

Identical function, current rating and coil specification. Made in China, direct replacement for 3RT1056-6AP36 with identical mounting dimensions, officially recommended replacement model

2. Upgraded model in same series: 3RT1064-6AP36 (AC-3 225A, 110kW)
3. Downsized model in same series: 3RT1055-6AP36 (AC-3 150A, 75kW)

Note: 3RT1056 manufactured in Germany; 3RT5056 manufactured domestically. Fully compatible in electrical performance and mounting hole layout, direct interchangeable in projects.

5. Installation & Maintenance Guidelines
6. Installation: Vertical mounting, tilt ≤ ±5°. Heat dissipation clearance required. S6 frame generates considerable heat; derating is required for multiple units mounted side-by-side inside cabinet.
7. Main circuit: Busbar connection, tighten to specified torque per datasheet to prevent overheating and contact burning.
8. Coil: Wide-range AC/DC coil, compatible for AC and DC control. 3RT19 surge suppression module is recommended in parallel to reduce interference to PLC digital outputs.
9. Contact life: Under AC-3 motor duty, mechanical life approx. 10 million operations; electrical life depends on breaking current.
10. Troubleshooting

Coil energized but no pull-in: Measure coil voltage, check coil open circuit or mechanical jamming

Pull-in but no continuity on main circuit: Loose busbar or burned main contacts

Chattering / abnormal noise: Low coil voltage, accumulated dust on iron core, spring fatigue

6. Customs HS Code

85364900 (Electromagnetic contactor)

7. Optional Spare Parts & Accessories

Thermal overload relay: 3RU2156 series (for 90kW motor)

Surge suppressor: 3RT1955-1CD00 (RC circuit), 3RT1955-1DG00 (Varistor)

Auxiliary contact block: 3RH1951 (for extra auxiliary contacts)

Arc shield & main contact repair kit: 3RT1956 contact assembly

Comparison Table: SIEMENS 3RT1056-6AP36 VS 3RT5056-6AP36

Both models feature identical electrical parameters, mounting dimensions and compatible accessories for direct replacement. The core differences lie in origin, nameplate marking, lead time and applicable certifications.

Key Notes

1. Interchangeability: SIEMENS officially approves direct replacement. No modification required for cabinet cutout, busbar, secondary control loop or thermal relay selection. Electrical characteristic curve, temperature rise and contact breaking capacity are identical.
2. Selection Guidance

✅ Choose 3RT5056: Domestic projects, budget control, fast delivery; preferred for most domestic panel building projects.

✅ Choose 3RT1056: Export machinery, overseas site, specification explicitly requiring German origin, mandatory UL/CSA certification.

3. Misconception Clarification: It is NOT a downgraded domestic variant. Same product platform and design, manufactured at different factories under identical design and test standards.

Supplementary: Shared Spare Parts List

Thermal overload relay: 3RU2156 series

Surge suppressor: 3RT1955-1CD00 / 3RT1955-1DG00

Main contact repair kit: 3RT1956

Additional auxiliary contact block: 3RH1951

Application Scenarios for 3RT1056-6AP36 and 3RT5056-6AP36

Identical load capacity for both models, rated for 400V, 90kW 3-phase motor direct-on-line start (AC-3, 185A). Differences are only based on project location, certification requirements and client procurement specification, NOT load capacity.

1. Common Applications (Both Models Applicable)

(1) Direct-on-line Motor Starting (Main AC-3 Duty)

Water pumps, sewage pumps, circulating pumps (water treatment, HVAC, building, chemical industry)

Air compressors, large fans, smoke exhaust fans

Conveyors, mixers, extruders, crushers (food, building material, mining)

Chillers and large refrigeration compressors for central air conditioning

MCC motor control centre drawer units for 90kW motor circuits

(2) AC-1 Resistive Load

High-power heating elements, resistance furnaces

Main circuit switching of high-power circuits inside distribution cabinets

(3) AC-6B Capacitor Switching

Capacitor bank switching for reactive power compensation cabinet (reactor required to suppress inrush current)

Matching: 3RU thermal relay for motor overload protection; 2NO+2NC auxiliary contacts for PLC running feedback and fault interlock.

2. Preferred Scenarios for 3RT5056-6AP36 (Domestic Local Version)
3. Domestic panel projects, domestic factories, HVAC, water supply & drainage, general factory automation

Complete CCC certification for domestic projects, sufficient stock and cost advantage, preferred by most EPC and cabinet manufacturers.

2. Domestic municipal projects: Wastewater treatment plants, municipal pump stations, building HVAC cabinets
3. Domestic machinery OEM: Fans, air compressors, chiller units sold in domestic market
4. Ordinary motor circuits in domestic power plants, metallurgy and chemical plants (no mandatory imported component requirement by client)
5. Retrofit replacement for old contactors, tight budget and fast delivery required

✅ Suitable for: Domestic projects without mandatory UL/CSA certification or German origin requirement

3. Preferred Scenarios for 3RT1056-6AP36 (German Imported Version)
4. Export machinery & equipment (export to Southeast Asia, Middle East, Europe and other overseas sites)

Full set of international certifications CE, UL, CSA to meet overseas owner and customs requirements.

2. New construction projects of foreign-invested factories where technical specification explicitly requires SIEMENS components made in Germany
3. Overseas EPC projects, control cabinets exported together with equipment, certificate of origin required
4. High-end pharmaceutical and semiconductor foreign projects where imported components are specified by client
5. Spare part replacement for legacy equipment: Original unit fitted with 3RT1056 and client requires identical OEM spare parts

✅ Suitable for: Export machinery, overseas projects, client specified imported components, mandatory UL/CSA certification

4. Selection Pitfall Avoidance
5. Identical load rating: Both can drive 90kW motors. 3RT5056 has no limitation for heavy-duty applications; only differs in origin and certification documents.
6. For domestic projects without “imported contactor” clause in specification, 3RT5056 is preferred for shorter lead time and better price.
7. For export to Europe / North America, select 3RT1056 and confirm in advance whether UL/CSA certificates are required.
8. Heavy vibration & dusty heavy industry environments (mining, cement plant): Both have identical mechanical life. Installation and heat dissipation requirements are the same; selection only depends on origin requirement.
9. Non-Applicable Scenarios

Direct-on-line starting for motor power exceeding 90kW; soft starter recommended for higher power.

Frequent jogging, frequent forward/reverse AC-4 duty (accelerated contact wear, derating evaluation required)

Safety circuits and emergency stop safety functions (SIEMENS safety contactor 3RT2 series should be adopted)