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Relay Overview
This electronic overload relay protects AC motors against thermal damage. You can install Allen-Bradley 193-EF1A directly onto NEMA or IEC contactors. The device monitors motor current and trips when exceeding safe limits. It provides adjustable trip settings for various motor sizes.
Technical Specifications
| Parameter | Value |
|---|---|
| Dimensions (W x H x D) | 55 mm x 85 mm x 75 mm |
| Weight | 0.18 kg |
| Rated current range | 1.0A to 5.0A (adjustable) |
| Maximum voltage | 600V AC |
| Frequency rating | 50/60 Hz |
| Trip class | Class 10, 20, or 30 (selectable) |
| Trip accuracy | ±5% of set current |
| Reset method | Manual or automatic (selectable) |
| Phase loss protection | Yes (within 3 seconds) |
| Ground fault sensitivity | None (basic overload only) |
| Status indication | 1 red LED (trip) |
| Output contacts | 1 N.O. auxiliary + 1 N.C. alarm |
| Contact rating | 5A at 240V AC |
| Total components | 42 discrete parts |
| Energy storage type | None (self-powered from current) |
| Operating temperature | -20°C to +60°C |
Relay Construction and Components
The relay contains a current transformer for each motor phase. An electronic circuit evaluates the sensed current against adjustable setpoints. Moreover, 42 discrete parts include trip timing circuits and output relays. The device draws operating power from the monitored current itself. Consequently, the relay needs no external control power supply.
Installation Process
You can mount Allen-Bradley 193-EF1A directly onto compatible NEMA or IEC contactors. The three phase conductors pass through built-in current transformers. Furthermore, a front panel dial adjusts the full load ampere setting. A push-button allows manual reset after fault clearance.
Performance Advantages
This relay provides selectable trip classes 10, 20, or 30 for different motor types. The phase loss protection trips within 3 seconds of detecting an open phase. Therefore, the motor does not run single-phased to destruction. The self-powered design also simplifies retrofitting into existing motor starters.
Safety and Compliance
Allen-Bradley 193-EF1A meets UL 508, CSA, and CE standards. The relay stores no electrical energy after power removal. Hence, technicians face no shock hazard during installation or replacement.