Tesla | Thermal Overload Relay 6-8A Adjustable | Manual or Automatic Reset
The Tesla D1312 is a thermal overload relay with a trip current adjustable from 6 to 8A, fitted to protect a motor against sustained overcurrent. The D1312 mounts directly to the matching Tesla contactor frame sizes and opens its contact when current stays above the dial setting long enough to heat the motor. Tesla lists the relay with manual and automatic reset options.
A contactor energises and isolates a motor circuit, but it does not monitor what that motor draws while running. A blocked impeller, a failing bearing, or a jammed conveyor sustains current above nameplate for minutes at a time. Winding insulation degrades well before the upstream protective device registers a fault condition. A thermal overload relay models that heating curve and interrupts the control circuit first. The 6 to 8A adjustment range is calibrated against the motor nameplate rather than the circuit rating.
Replacing a tripped or damaged overload on an existing starter is a component swap rather than a switchboard rebuild. The D1312 covers the 6 to 8A band, which suits a common spread of smaller motors driving pumps, fans, and conveyors. Because Tesla lists manual and automatic reset options, one part number services an attended plant room and an unattended pump installation. Carrying one or two on the van converts a breakdown callout into a same-visit repair.
Features
- 6 to 8A adjustment range — the dial sets trip current anywhere between 6 and 8A to match the motor nameplate figure.
- Sustained overcurrent response — the D1312 acts on prolonged overload rather than on momentary current peaks.
- Start-up inrush tolerance — the thermal element rides through the brief inrush a motor draws at start and reacts to load that stays high.
- Manual or automatic reset — Tesla lists both reset modes, so one part number covers attended and unattended plant.
- Direct contactor mounting — the D1312 fits the matching Tesla contactor frame sizes without a separate mounting kit.
- Front-mounted current dial — the setting adjusts from the face of the relay once it is fitted to the contactor.
- Industrial application — Tesla specifies the D1312 for machinery and equipment that need overload protection in industrial service.
- Set to nameplate current — the dial matches motor full load current, not the rating of the protective device feeding the starter.
- Not short-circuit protection — a thermal overload relay acts on sustained overload, so the circuit still needs separate fault protection upstream.
- No trip class published — the Tesla datasheet gives the adjustment range and contactor fit but publishes no trip class or voltage rating.
- Licensed installation required — the D1312 forms part of a motor control circuit, and Sparky Direct supplies it for installation by a licensed electrician.
- One year warranty — a one year warranty applies for domestic and commercial use, handled as a return to Sparky Direct.
Where to use
- Pump sets — the D1312 protects transfer, pressure, and irrigation pump motors drawing within the 6 to 8A band.
- Fans and blowers — covers extraction and ventilation motors on long duty cycles, where a fouled impeller loads the motor steadily.
- Conveyors — protects conveyor drives where a jam raises running current without producing a short circuit.
- Compressors — suits smaller compressor motors that run under sustained load between cut-out points.
- HVAC plant — protects smaller motor-driven equipment in air handling and refrigeration installations.
- Workshop machinery — fixed machines with a motor in the 6 to 8A band run through a starter fitted with the D1312.
- Starter repairs and upgrades — swaps into an existing starter when the fitted relay is damaged or its band no longer suits the motor.
A thermal overload relay is not short-circuit protection. The D1312 acts on sustained overcurrent, so the motor circuit still needs a separate protective device for fault current. Tesla publishes the adjustment range and the contactor frame fit but no trip class or voltage rating, so confirm both against the starter and the supply before specifying it. Setting the dial to anything other than the motor nameplate current defeats the protection the relay is there to provide.
