Overview
The Siemens 3UA55 00-1K overload relay is a proven bimetal protection device for AC and DC motors. This model is rated for 8-12.5A operation and provides accurate overload detection with built-in temperature compensation. The relay delivers reliable protection against motor overload and single-phase failure conditions, making it essential for safe motor-driven equipment operation in industrial control systems.
Key Features
- Bimetal thermal sensing element with automatic thermal reset
- Temperature compensation for stable operation across ambient conditions
- Single-phase failure detection on 3-phase motors
- Manual or automatic reset modes available
- Direct mounting on 3TF44/45 and compatible contactor types
- Rated insulation voltage: 690 V AC
Technical Specifications
- Rated Current Range: 8–12.5 A
- Rated Insulation Voltage: 690 V AC
- Series Type: 3UA55 Bimetal Relay
- Mounting: Direct mounting on contactor
- Reset Function: Manual/Automatic selectable
- Operating Principle: Bimetal thermal element
- Protection Functions: Overload and phase-failure protection
- Manufacturer: Siemens
Typical Applications
The 3UA55 00-1K is commonly applied in:
- 3-phase AC motor starters and soft-start systems
- Machine tool control circuits with motor protection requirements
- Pump and fan motor protection in industrial plants
- General industrial motor control panels
- OEM equipment requiring reliable overload sensing
Compatibility & Replacements
The Siemens 3UA55 00-1K is designed for use with Siemens 3-phase motor contactors in the 3TF series (3TF44, 3TF45) and similar mounting configurations. It is a direct replacement for worn or failed 3UA55 00-1K units. Users seeking alternative protection methods may also consider solid-state overload relays from Siemens or equivalent protection modules, though compatibility and current ratings must be verified. This relay is part of the extensive Siemens 3UA family, which covers motor currents from 0.1 A to 400 A across multiple amp ranges.
