GR-WM2 High Torque Gearmotor, 149:1 Ratio with Encoder


The GR-WM2 (2019 version) is a DC motor and gearbox combination featuring a three-stage 149.25:1 reduction gearbox, both 12V and 24V motor options are available. 

For the 12V option (run at 12V) the no-load speed is 49rpm and the maximum sustained torque at the output shaft is 30kg-cm at 41rpm, with a maximum peak of over 150kg-cm. 

For the 24V motor (run at 24V) the no-load speed is 45rpm and the maximum sustained torque is 35kg-cm at 38rpm, also able to generate >150kg-cm for brief periods. 

The first gearbox stage is a worm-and-wheel meaning that the transmission cannot be back-driven once in position. The gearbox is very sturdy outside and in, with larger-pitch gears than found in cheap gearboxes of a similar size, allowing it to transfer and support higher torque loads without the gear teeth breaking. A 12mm output shaft with dual ball-bearing support means that relatively large loads can be mounted directly to the output shaft.

Please see further operating details under the 'technical details' below.


£47.00 £56.40 inc VAT
Options:
Quantity:
In Stock
Group SKU: GR-WM2-2019

This motor model, newly updated in 2019 with both 12V and 24V options and a hall sensor encoder, provides an ideal solution for applications requiring a high output torque from a compact device. The right-angle gearbox also enables the motor to fit into positions that planetary and conventional spur gear motors wouldn't be able to. The 2019 update also sees a small change to the gearbox, incorporating a brass-nylon first gearbox stage to reduce noise levels. 

Special effects, DIY, robotics and automation projects can all benefit from the steady output speed and the resistance to being rotated (self-locking property) which is provided by the worm-and-wheel stage once the motor is in a position. The 12mm output shaft and output gear stage is much stronger than that of similar motors on the market, meaning that larger radial loads can be supported without causing damage to the gearbox. 

As with any brushed DC motor it is possible to vary the output speed by regulating the supplied current with a DC motor speed controller, and to change the direction of rotation by swapping the polarity of the supplied current. We also stock power supplies, rocker switches, and remote switches that are ideal for controlling these motors. 

The motor is a '565' type, with a 36mm can diameter. It features a cooling fan towards the rear of its body to enable high duty cycle operation (the maximum allowable duty cycle depends on the size of the load). Be careful that debris does not enter the cooling vents which could damage the motor. Especially for high duty cycle usage ensure that the rear of the motor is well ventilated.


Integrated Encoder

The motor has a hall-sensor based quadrature encoder mounted to its rear. The encoder is powered by two leads (+Vcc Blue, -GND Green) and can run from a DC supply of between 5-24V. It has a dual-channel output (channel A Yellow lead, Channel B White lead), with each channel generating 16 pulses per rotation of the motor itself, meaning 16 x 149.24675 = ~2388 pulses per rotation of the output shaft. One of the channels is out of phase with the other, as such it is possible to tell both the speed (from pulse frequency) and direction (by reading the pulses of one channel and comparing it to the other) of the motor. The nature of the signals that are generated is illustrated below. Given a maximum no-load motor speed of 49rpm for the 12V motor (when at 12V) the pulse frequency may be up to 1951Hz per channel (or the frequency rate may be greater than this if your controller is counting rising/falling edges as opposed to HIGH/LOW signal states). 


Lead Options

Each motor is supplied with a set of 6 small leads with a 2.54mm female connector on the end which run to the encoder (hall sensor) PCB on the rear of the motor. If you are only ever running low loads, with the motor drawing less than 1A, then you may use this connector to power the motor directly via the red and black leads, the other connections are also shown below:


GR-WM2 6-pole encoder connector female. Motor and hall sensor connectors

If you are running higher loads (and the motor is drawing >1A), then whilst this lead can still be used for encoder connections, you will need to add larger cables and connectors for powering the motor itself. You can solder wires on to the two tabs either side of the encoder PCB, or we offer options (selectable above) to supply the motor with either a male DC connector lead (2.1 x 5.5mm barrel type), which extends 250mm from the motor, or for two (red and black) 1mm2 silicone-insulated leads with tinned ends running 500mm from the motor. If a lead option is added please allow for up-to an additional working day to process your order.


This motor is similar in size to the GR-WM1 model that we also stock, though the GR-WM1 model is not available with encoder feedback.

Major dimensions for the motor are illustrated below. Scroll down to 'Technical Details' for construction details and operating specifications.


Encoder Control Detail


Gearbox Build Detail
Size:The gearbox body has dimensions of 58 x 58 x 37mm excluding the output shaft
The motor is a maximum of 37.5mm in diameter by 71mm long (without either lead option fitted)
The overall motor and gearbox size including the output shaft is 129 x 58 x 58mm
Mounting:Three M4 (5.5mm deep) threaded holes on the side face of the gearbox (the same side that the output shaft extends from)
Body material:Sintered steel and aluminium
Gearbox:First stage (worm-wheel, brass worm, low-noise nylon wheel) 2:26 13/1
Second stage (steel spur gears) 11:34 34/11
Third stage (steel spur gears) 7:26 26/7
Total reduction 11492/77 : 1     Decimal 149.24675 : 1
Shaft type:Steel, 12mm diameter by 21mm long with a 16mm long 'D' flat
Shaft support:Dual 12mm roller ball bearings
Weight:750g (without optional motor leads)


Operating Characteristics with 12V DC motor option (values at output from gearbox)

at 6V DC:
at 12V DC:
No-load speed after gearbox:25rpm49rpm
No-load current:0.4A0.5A
Continuous rated torque, speed: 15kg-cm at 135rpm
30kg-cm at 41rpm
Continuous rated current:
1.5A2.4A
Continuous rated output power:5.68W23.1W
Maximum power torque, speed:56kg-cm at 13rpm113kg-cm at 26rpm
Maximum power current:3.2A6.3A
Maximum power output:
7.5W30W
Stall torque:
113kg-cm (11.1Nm)226kg-cm (22.2Nm)
Stall current:
6.5A*
12.9A*

*Warning: Avoid reaching stall by adding circuit or load protection, the motor will quickly overheat and be damaged if it is held in a stall condition

Please be aware that some of the values above are extrapolated from other measurements and there will be a small degree of variance from motor to motor, allow for a safety factor of 10% above/below the given values when designing for your application. Be sure that any equipment that you use with the motor (power source and controller) is capable of handling the currents that the motor may demand.


Operating Characteristics with 24V DC motor option (values at output from gearbox)

at 12V DC:
at 24V DC:
No-load speed after gearbox:23rpm45rpm
No-load current:0.2A0.3A
Continuous rated torque, speed: 17.5kg-cm at 135rpm
35kg-cm at 38rpm
Continuous rated current:
0.8A1.5A
Continuous rated output power:5.68W23.1W
Maximum power torque, speed:57kg-cm at 11rpm115kg-cm at 23rpm
Maximum power current:2.1A4.1A
Maximum power output:
6.4W27W
Stall torque:
115kg-cm (11.3Nm)231kg-cm (22.7Nm)
Stall current:
4.2A*
8.3A*

*Warning: Avoid reaching stall by adding circuit or load protection, the motor will quickly overheat and be damaged if it is held in a stall condition

Please be aware that some of the values above are extrapolated from other measurements and there will be a small degree of variance from motor to motor, allow for a safety factor of 10% above/below the given values when designing for your application. Be sure that any equipment that you use with the motor (power source and controller) is capable of handling the currents that the motor may demand.



Gearbox Mounting Pattern

The face of the gearbox on the output shaft side has three M4 x 5.5mm tapped holes in the positions shown below which can be used to mount the motor. 


CAD models are available for the motor, please contact us for a copy, or if you have any other technical questions about the item.

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