GR-SENS Adjustable Current-Limiting Protection Switch

This product is now discontinued, effectively replaced by the GR-MOT1 motor controller which includes independently adjustable directional current limiting and many other features. Please do contact us if you have any questions or require support for your GR-SENS.

The GR-SENS V2023 is a compact fast-response overcurrent protection device, suitable for use with DC electric motors and actuators of many different shapes and sizes. It is designed to measure the current drawn by a motor/actuator and if it exceeds a Threshold Current (adjustable between 1-15A) for longer than a Sensitivity Time (also adjustable, between 5-600ms) then the output is quickly turned off and the device illuminates Red to indicate a trip. A user can reset the device if it has tripped simply by turning the input off and then on again, or by reversing the input polarity (usually done via a controller or a switch). 

There are only four wires to connect: Two input wires with an in-line 20A fuse (acting as a failsafe), which should be connected to the output of your controller or switch, and two output wires which you should connect to your DC motor or actuator. 

Regular price £29.00
Regular price £36.80 Sale price £29.00
(each, exc VAT)

Availability: OUT OF STOCK

Contact Us to Pre-Order


This device, exclusive to Gimson Robotics, provides a significant improvement over the basic circuit protection used in many automation circuits. It is capable of rapidly disconnecting power to a connected motor or actuator in the event of an overload. By allowing a user to adjust both a Threshold Current and Sensitivity Time value, the response to an overload can be fine-tuned to the application, offering a much faster and more predictable response than thermal devices such as fuses or circuit breakers. 

The switch automatically resets itself if the input current is turned off and on again OR if the input polarity reverses/inverts, so you'll no longer need to go hunting for the correct size fuse or to find a tiny reset switch after an overload. These characteristics allow the GR-SENS to be used as a current-based limit switch in installations where it is difficult to mount a conventional limit switch circuit, since if it trips in one direction it then allows the user to reverse back in the opposite direction, away from the overload. 

A single RGB (multicolour) LED provides handy visual feedback of your circuit state. In normal operation this will be solid BLUE or GREEN, indicating the active control mode (where BLUE mode allows current threshold adjustment between 1-6A and GREEN mode allows adjustment between 1-15A). If the device 'trips' due to an overcurrent event, with the output turning off, the LED will illuminate either solid RED for a standard trip (according to the CURR and SENS dial positions), or will flash RED repeatedly if the device registers over 20A for over 30ms, which is a non-adjustable upper limit.

It is an entirely solid-state switching device, using fets rather than mechanical relays to ensure reliable long-term operation. 

The response of the controller is illustrated by the graphs below. Put simply, if the detected current exceeds the Threshold Current setting for LESS than the Sensitivity Time (as shown in the first graph, where t1 is less than the sensitivity time setting) then the device will not trip and current will continue to flow, however if the current exceeds the threshold for MORE than the Sensitivity Time then the output will be turned off and the current will go to zero (shown in the second graph, where t2 equals the time setting and the controller turning the output off is shown by the vertical fall in current).

Small screw-dials (adjusted with a small flat head or phillips screwdriver) allow you to tune the settings of each device. The available adjustments for Threshold Current are shown below for the two controller versions, the dials offer linear adjustment between two values. 
To change between the two overcurrent threshold modes (higher current and lower current limiting), follow the steps below.

Instruction sheets are included with each device, please click on the link below to download a copy.

Download: GR-SENS V2023 Information Sheet (PDF, 3.6MB)

Copies of the references sheets for older discontinued versions of the GR-SENS are also available:
GR-SENS V2.1 Information Sheet, 15A Version (PDF, 1.8MB)
GR-SENS V2.1 Information Sheet, 5.5A Version (PDF, 1.8MB)


Device Specifications
Operating Voltage
8 - 28V DC
Current Threshold Adjustment
BLUE Mode: 1-6A, GREEN Mode: 1-15A
Time Sensitivity Adjustment
Maximum Limit Threshold
20A for >30ms. Red LED should flash to indicate if this level has been breached
Operating Temperature
-5°C ~ +40°C
Ensure that there is free air flow around the device to prevent overheating
Duty Cycle Rating
For battery or regulated power supply input: 100% duty at 5A, maximum 20A duty at 15A (2 minutes maximum continuous). For PWM controller input: 15% maximum duty (60seconds maximum continuous) at up-to 10A
45g, including screw terminals
Input Lead
120mm long 16AWG high temperature silicone insulated high strand count cables, with micro automotive (type APS or ATT) blade fuse holder and 20A fuse in-line with one of the two wires
Output Lead
70mm long 16AWG high temperature silicone insulated high strand count cables
Input & Output Connectors
15A-rated screw terminals
Operating Environment
0°C ~ +40°C
Ensure that the device is protected against water or extreme humidity
Product Standards
Tested to BS EN IEC 61000-6-3:2021 and BS EN IEC 61000-6-1:2019

Contact us if you have any questions about this device, including for customisations and bulk ordering.