• black icon of a bullhorn 30 years industry experience
  • black icon of three cubes Over 8,000 products in stock
  • Black icon of a clock Order by 16:00 and receive the next working day

CROUZET CONTROL

Temperature monitoring relays HT81, HWT81 - OBSOLETE

Control relay for temperature monitoring in lift machinery rooms, used for monitoring of temperatures between +4 °C and +40 °C per the EN 81 standard.

HT81 : As long as the temperature that is controlled by the PT100 sensor is between the two limit values, which are preset at the front, the relay output is activated and the yellow LEDs are on.

When the temperatures is over or under one of these limit values (upper or lower), the time delay (Tt), which is set at the front, begins to count down. The yellow LED for the set limit value (upper or lower) flashes. If the temperature is still too high or low after the time delay, the relay drops out and the yellow LED turns off. As soon as the temperature returns to the set range, the relay activates (allowing for a certain response time). If the PT100 sensor is incorrectly connected (open circuit or short circuit), the relay drops out and the three LEDs flash.

HT81-2: Same function as above except with 2 relay outputs.

HWT81: As long as the temperature that is controlled by the PT100 sensor is between the two limit values, which are preset at the front, the relay output is activated and the yellow LEDs are on. When the temperature passes one of the set limit values (upper or lower), the time delay (Tt) is activated, which is also set at the front. The yellow LED R1 for temperature flashes. Once the delay has passed, the relay drops out and the LED turns off if the temperature still exceeds the set limit values. The relay output R1 activates immediately as soon as the temperature is between the preset limit values.

The relay also monitors the phase sequence L1, L2 and L3 in the 3-phase network as well as total phase interruption, even during regeneration (returned voltage) of the phase (<70 %). After an activation delay and for as long as no phase faults exist, R2 is activated and the LED R2 turns on. When a fault occurs, the relay drops out and the LED R2 turns off. Once the fault is corrected, the relay re-activates and the LED R2 turns on again. If the PT100 sensor is incorrectly connected (open circuit or short circuit), the relay output R1 deactivates and the LED R1 flashes.

Read more
  • OBSOLETE WITH NO REPLACEMENT
  • Temperature monitoring, lift machinery room per EN81
  • Adjustable control between +4°C and +40°C
  • PT100 input
  • Phase monitoring

Selected variant

Selected variant

Technical data

Approvals CSA, GL, RoHS, UL
Breaking capacity 5A, 250V AC/DC
Function Under/Overtemperature
IP class connection IP20
IP class housing IP30
Lower limit -1 - 11°C
Output Relay 1 pole C/O
Sensor cable length max 10 m
Storage temperature max 70 °C

*Invisible Heading*

Storage temperature min -40 °C
Supply voltage 24-240V ac/dc
Temperature operational max 50 °C
Temperature operational min -20 °C
Time delay startup 0,2 s
Time delay when exceeding the limit value 1-10s
Upper limit 34 - 46°C
Weight 121 g

Measurements and connections

Control relay dimensions

Control relay HT81

HT81
1: F1: Fast-blow fuse 1 A (recommended)

Product description

Control relay for temperature monitoring in lift machinery rooms, used for monitoring of temperatures between +4 °C and +40 °C per the EN 81 standard.

HT81 : As long as the temperature that is controlled by the PT100 sensor is between the two limit values, which are preset at the front, the relay output is activated and the yellow LEDs are on.

When the temperatures is over or under one of these limit values (upper or lower), the time delay (Tt), which is set at the front, begins to count down. The yellow LED for the set limit value (upper or lower) flashes. If the temperature is still too high or low after the time delay, the relay drops out and the yellow LED turns off. As soon as the temperature returns to the set range, the relay activates (allowing for a certain response time). If the PT100 sensor is incorrectly connected (open circuit or short circuit), the relay drops out and the three LEDs flash.

HT81-2: Same function as above except with 2 relay outputs.

HWT81: As long as the temperature that is controlled by the PT100 sensor is between the two limit values, which are preset at the front, the relay output is activated and the yellow LEDs are on. When the temperature passes one of the set limit values (upper or lower), the time delay (Tt) is activated, which is also set at the front. The yellow LED R1 for temperature flashes. Once the delay has passed, the relay drops out and the LED turns off if the temperature still exceeds the set limit values. The relay output R1 activates immediately as soon as the temperature is between the preset limit values.

The relay also monitors the phase sequence L1, L2 and L3 in the 3-phase network as well as total phase interruption, even during regeneration (returned voltage) of the phase (<70 %). After an activation delay and for as long as no phase faults exist, R2 is activated and the LED R2 turns on. When a fault occurs, the relay drops out and the LED R2 turns off. Once the fault is corrected, the relay re-activates and the LED R2 turns on again. If the PT100 sensor is incorrectly connected (open circuit or short circuit), the relay output R1 deactivates and the LED R1 flashes.

Accessories

Related

Katko switch disconnectors
Product news

Switch disconnectors from Katko

We have now added switch disconnectors to our range! Switch disconnectors contribute to the overall functionality and safety of electrical systems.

Lutz loccbox mini circuit breaker
Product news

LUTZE LOCC-Box

LOCC-Box from Lutze is an intelligent current monitoring device that provides reliable protection of DC circuits in a slimline 8.1mm housing.

Push In Technology such as push-in terminals, push-in sockets, and even push-in heaters.
Blog

The Push In Technology You Need at OEM Automatic

OEM Automatic has integrated push-in technology into it's product offering for many years now. In this blog post, we'll explore the various benefits of push-in technology and some of the products we offer that make use of this innovation, such as push-in terminals, push-in sockets, and even push-in heaters.

Kubler encoders and process displays
Blog

Combine Encoders and Process Displays with Kubler

We present Kublers ultimate package: Encoders and Process Displays, which can be used together to create efficient processes.

DF Electric is a company that specializes in the production of electrical components, including fuses fuse holders and transformers
Product news

DF Electric Fuses, Fuse holders and Transformers

Let’s tell you a little about DF Electric – our supplier of fuses, fuse holders and transformers, and how they are a simple but essential product for all users of electrical components.

Visit OEM and AGRO at Vehicle Electrification Expo
Company news

Join us at Vehicle Electrification Expo in Birmingham

OEM Automatic is thrilled to announce its participation in the UK's largest dedicated event for electric and hybrid vehicles - the Vehicle Electrification Expo! We will be exhibiting with our supplier, Agro, to showcase EV EMC cable gland solutions for sustainable and eco-friendly practices. Find us on stand 921 with Agro.

Parts Measurement range Output Price
Relay 1 pole C/O
Fasövervakning 208-480V AC 2x Relay
2x Relay

Selected variant

Select a variant in the list

Contact us

If you need any help, you can contact us in one of the following ways:

phone 0116 284 9900

Send an e-mail Send an e-mail

comments Use live chat