Temperature Control
Preset Built-in Thermostat
Pre-set built-in thermostats provide a low cost means of temperature control for heaters. The thermostat is normally wired directly into the heater circuit. If the current draw of the heater exceeds the rating of the thermostat, external leads are provided.
The thermostats are normally mounted over a heated section to sense the heater’s temperature or optionally over a cold section to indirectly sense the temperature of the load. The thermostat is enclosed in a molded silicone rubber housing and permanently attached to the heater.
| Snap Action Thermostat | Creep Action Thermostat | |
| Action | Quick cutout on rise to temperature. The contacts will open on rise when the temperature increases to the snap point of the calibrated bimetal disc. | Sustained response, and a slow cutout at the trip point. The creep action thermostat has a slow make/slow break action around setpoint. |
| Set point (opens) | available from -30 to 250°C in 10°C increments, close at 10 - 30°C - below setpoint. Manual reset version available | available in a limited selection from 50 to 250°C in 10°C increments. |
| Electrical | 125 Vac, 15 Amp, 250 Vac, 10 Amp |
120 Vac, 15 Amp 250 Vac, 10 Amp |
Adjustable Thermostat
Adjustable thermostats allow the user to set a specific temperature and attain a desired result. The thermostat is encapsulated in a silicone rubber housing. This can often be found in large size regular shaped drum heaters and heating blankets.
Current rating: 12.5A @ 125V, 6.5 A @ 250V
Temperature range: 0 -150°C. Consult Sinomas for more option.
Built-in temperature sensors
The sensors can be mounted on the heater to sense the temperature of the part being heated or the heater surface temperature itself. Thermal fuses can be incorporated into the design to prevent dangerous temperatures in the event of a control device failure.
Thermocouples - Standard thermocouple temperature ranges apply. Specify when ordering.
Thermistors - Thermistors are also a resistive-based temperature sensor. They do not generally respond in a linear style and are used in a limited temperature range or at a specific single temperature. Small bead style thermistors can be mounted directly on the heater. The thermistor’s response is generally designed directly into the customer’s electronic control system. Therefore if a thermistor is required, specify manufacturer, specific model number, type and specifications when requesting a quote.
RTD - Mostly PT100 film temperature sensor.
Built-in Thermal Fusing
Thermal fuses (cutoffs) are used as high limit protection devices to guard the object being heated from dangerous temperatures in the event of a primary control device failure. The thermal fuse can be mounted using various methods depending on other options. If the heater does not have a thermostat, the thermal fuse would be mounted under the lead exit patch. If used in conjunction with a thermostat, it could be mounted under the thermostat cover.