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3UA Series Motor Protection Thermal Overload Relay
3UA Series Motor Protection Thermal Overload Relay
3UA Series Motor Protection Thermal Overload Relay
3UA Series Motor Protection Thermal Overload Relay
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3UA Series Motor Protection Thermal Overload Relay
3UA Series Motor Protection Thermal Overload Relay
3UA Series Motor Protection Thermal Overload Relay
3UA Series Motor Protection Thermal Overload Relay
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LR2K Series Thermal Overload Protection Relay LR2K0301-0312
LR2K Series Thermal Overload Protection Relay LR2K0301-0312

3UA Series Motor Protection Thermal Overload Relay

Size:Miniature
Brand Name:Newtrend
Theory:Electromagnetic Relay
Place of Origin:China
application:General Purpose
Model Number:3UA
Contact Load:High Power
Protect Feature:Sealed
SKU: 60043008521 Category:
Description

3UA series thermal overload relay is suitable for using in power system with AC 50/60Hz, rated operation voltage up to 660V and 1000V, current from 0.1A to 630A. It is used to protect AC three-phase asynchronous motor against overload and open-phase.

The current setting value can be regulated and the setting current values of many thermal elements are intercrossing overlepping arrangement, for easy selecting by the customers from -25Ûc to +55Ûc air temperature as the products have temperature compensating. The relays have the test push-button for breaking NC contacts, the operating indication and free trip characteristics. The items conform to IEC60947-5.

 

Specifications
Type
Rated operating current (A)
Rated insulation voltage (V)
Current setting range (A)
3UA50
12.5
660
0.1~0.16, 0.16~0.25, 0.25~0.4, 0.32~0.63,

0.63~1.0, 0.8~1.25, 1.0~1.6, 1.25~2.0,

1.6~2.5, 2.0~3.2, 2.5~4.0, 3.2~5.0,

4.0~6.3, 5.0~8.0, 6.3~10.0, 8.0~12.5
3UA52
25
660
0.1~0.16, 0.16~0.25, 0.25~0.4, 0.4~0.63,

0.63~1.0, 0.8~1.25, 1.0~1.6, 1.25~2.0,

1.6~2.5, 2.0~3.2, 2.5~4.0, 3.2~5.0,

4.0~6.3, 5.0~8.0, 6.3~10.0, 8.0~12.5,

10.0~16.0, 12.5~20.0, 16.0~25.0
3UA54
32
660
4.0~6.3, 6.3~10.0, 10.0~16.0, 12.5~20.0,

16.0~25.0, 20.0~32.0, 25.0~36.0
3UA58
80
1000
16.0~25.0, 20.0~32.0, 25.0~40.0, 32.0~50.0,

40.0~57.0, 50.0~63.0, 57.0~70.0, 63.0~80.0
3UA59
63
660
0.1~0.16, 0.16~0.25, 0.25~0.4, 0.4~0.63,

0.63~1.0, 0.8~1.25, 1.0~1.6, 1.25~2.0,

1.6~2.5, 2.0~3.2, 2.5~4.0, 3.2~5.0,

4.0~6.3, 5.0~8.0, 6.3~10.0, 8.0~12.5,

10.0~16.0, 12.5~20.0, 16.0~25.0, 20.0~32.0,

25.0~40.0, 32.0~45.0, 40.0~57.0, 50.0~63.0
3UA62
180
660
55.0~80.0, 63.0~90.0, 

80.0~110.0, 90.0~120.0, 

110.0~35.0, 120.0~150.0, 

135.0~160.0, 150.0~180.0
3UA66
400
1000
80.0~125.0, 125.0~200.0,

180.0~250.0, 200.0~320.0, 
250.0~400.0
3UA68
630
1000
320.0~500.0, 400.0~630.0

 

Additional information
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Technical Datasheet & Downloads

📄 Technical Documentation & Product Specifications

Download official engineering datasheets, certified test standards (IEC / UL / CE), wiring diagrams, and dimensional drawings for 3UA Series Motor Protection Thermal Overload Relay.

📥
Official Technical Datasheet (PDF) Complete electrical ratings, tripping characteristics, dimensions, and compliance specifications.
Request Official Datasheet (PDF)
📐
2D/3D CAD & Dimensional Drawings STEP, DXF, and PDF CAD drawing files for panel builders and switchgear designers.
Request CAD Model
Certified Standards: IEC 60898-1, IEC 60947-2, CE, RoHS, ISO 9001:2015
Manufacturer: Shanghai Newtrend Electric Co., Ltd. (Global Export Compliance)
Engineering Support: 24-hour response for custom voltage ratings, auxiliary contacts, and technical consulting.
Technical FAQ & Selection Guide

💡 Frequently Asked Technical Questions & Selection Guide

Pure engineering specifications, tripping curve parameters, and electrical selection guidance for panel builders and system designers.

AC-1 / AC-3 Duty

How to calculate contactor rating based on motor power and utilization categories (AC-1 vs AC-3 vs AC-4)?

A

AC-3 rating applies to standard squirrel-cage motor starting and stopping during normal run (starting current 5–7x In). For non-inductive or purely resistive heating loads, use the higher AC-1 rating. For severe inching, jogging, and plugging applications (AC-4 duty), derate the contactor or upsize by 1 to 2 frame sizes to prevent contact erosion.

Coil Voltage Selection

How to choose the correct control coil voltage, frequency, and electronic wide-voltage options?

A

Standard AC coils include 24V, 48V, 110V, 220V/230V, 380V at 50/60Hz. For DC control loops or PLC outputs, specify DC coils or electronic wide-range AC/DC coils (e.g. 100V–250V AC/DC) which feature built-in surge suppression, low holding power consumption, and immunity to voltage dips.

Overload Coordination

How to size and coordinate the matching thermal overload relay (TOR) for Type 2 protection?

A

Select a thermal overload relay whose current setting range straddles the motor full-load current (FLA). Set the dial precisely to 1.0x motor nameplate FLA. For IEC 60947-4-1 Type 2 coordination, pair the contactor and relay with backed-up upstream fuses or fast-acting MCB/MCCB to prevent welding under fault conditions.

Auxiliary & Interlocks

What auxiliary contact blocks and mechanical interlocks can be added for motor reversing?

A

Units feature built-in 1NO or 1NC auxiliary contacts, expandable with top-mounted 2-pole or 4-pole auxiliary contact blocks (F4 / AX) and pneumatic timer delay blocks. For forward/reverse motor starters or star-delta starter assemblies, add side-mounted mechanical interlock units (MI) with electrical interlocking.

Ambient & Altitude Derating

How do ambient temperature and installation altitude affect contactor performance?

A

Standard ratings are calibrated for -5°C to +40°C. For ambient temperatures exceeding 55°C or altitudes above 2000m (where reduced air density diminishes heat dissipation and dielectric insulation), derate operational current by 2% per 100m above 2000m and verify insulation voltage limits per IEC standards.

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