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General Guidelines for Use of Igarashi Motors

In handling Igarashi motors, be sure to take note of these general instructions to ensure correct, secure, and safe use of the motors. For more information, please contact us directly or our sales offices.

Handling and Usage

  1. Many Igarashi motors include tapped mounting holes in the housing for fixation of the motor in the application. Screws which intrude too far within the motor can contact and damage the inner components. Please consult the motor drawing for the maximum allowable intrusive screw length. If such detail is not on the drawing, or you do not have a drawing available, then we recommend consulting your local Igarashi applications engineering team.

  2. Be aware that some features on the motors, such as vent holes or endcap notches, may change in the event of new tooling or supplier changes. Please consult the Igarashi engineering or sales teams to request dimensional control of these features before referencing them in your application. In addition, any ventilation holes in the motor should not become blocked in the application without consultation with Igarashi.

  3. During assembling of a gear or a fan or some other item to the motor shaft please take care to avoid radial and axial loads transmitted to the motor body and bearings. Always remember that this can have a negative effect on the life and noise of bearings during operation. For press fitting a pulley, gear etc. on the motor output shaft always support only the shaft at the opposite end and avoid any contact to the motor case. Also be mindful of the axial load imparted to the shaft as it could cause shaft bending.

  4. Do not insert a motor terminal or lead wire into a home outlet. You might get an electric shock. When applying electric power, don’t touch a live part like a current-carrying terminal. You could get an electric shock. Touching a rotating component of the motor can cause injury.

  5. Be sure to select lead wires, switches, relays, motor driver ICs, or similar with proper current and voltage ratings in order to avoid the risk a failure, such as a burnout.

  6. It is best to confirm the performance and reliability of the motor for the customer’s application in the actual intended assembly (as opposed to motor only testing.) For example: Electric/mechanical characteristics, audible/electric noise, environmental storage/operation, influence from atmosphere/gas, reliability etc.

  7. The internal resistance of the motor power supply and use of the motor with high/low voltage or different from specified voltage, high current, and pulse-driven (including PWM) affect the performance, life and starting ability of the motor. If the operating temperature deviates from normal room temperature, please note the conditions.

  8. Insulation resistance between terminals, terminals and motor case or between commutator slits might reduce. For example, due to a completely worn-out carbon brush or specific environmental/use conditions. Take protective measures to prevent circuit burnout or short circuit between the motor case and power supply GND.

  9. Be aware that axial thrust on the output shaft produced by worm gears, fans, etc. can impart additional friction at the motor bearings which can impact the motor performance and may lead to reduced life.  

  10. Radial loads to the shaft from accessories such as a belt drive, spur gear, or heavy oscillating load such as produced by rotating eccentric cams, etc. and also by vibration given from outside results in similar impacts as axial thrust.

  11. Check the expected service life under the actual operating conditions by testing the motors assembled in your application. Heavy axial and radial loads may need to use some additional support to retain the shaft end.

  12. Intensive pressure to the case or endcap surfaces near the bearings might misalign the bearings and cause internal friction of the motor. Please take care for motor mounting not to push near the bearings or on the shaft. Specifically, be careful about any small-diameter motor, since its speed (rpm) changes depending on the fixing force. When pressing the motor into any cylindrical case, press the outer peripheral part of the housing/endcap.

  13. Don’t screw unevenly in fixing the motor. Do not apply any force that deforms the body of the motor. This might adversely affect the mounting surface flatness or characteristics of the motor.

  14. Don’t apply any force that presses into, pulls, or bends the motor terminal unless otherwise reviewed and agreed by Igarashi.

  15. Don't allow any adherence of binding agents to the bearings nor intrusion into the motors.

  16. Be careful and prevent oil or the grease from flowing in the motor. This might cause a failure.

  17. Please take care in case you need equipment which emits ultrasonic waves for the motor assembly. Some of the internal parts of the motor might be damaged.

  18. Soldering of terminals: In order not to develop thermal plastic deformation around the motor terminals nor to give them any forced bend or inward depression please finish your work quickly. Take care not to allow solder debris and flux to spatter into motor. If necessary cover up all nearby holes and apertures.

  19. Don’t touch the bearings of the motor. This might absorb and remove bearing oil or grease which may lead to bearing noise and/or reduced bearing life.

  20. Printed marking on motor case may be blurred or may fade out when rubbing. An example would be rubbing by packing material during shipping or by fixtures on your production line.

  21. Operation in vacuum or gas atmosphere (for example argon) may affect the motor performance or life.

  22. Gases generated from silicone materials, which contain low molecular silicone compounds deposit on the motor's commutator, brushes or other parts. Due to electric energy they break down into SiO2, SiC and other constituents which result in a rapid increase of the contact resistance between the commutator and brush. Furthermore, check as well that binding agents or sealing materials are not generating gases of detrimental nature (for example from cyanic adhesives and halogen gases) when used for the motor or during assembly of your product.

  23. Previously approved motor designs will require revalidation and review before use in a new application. It is recommended to consult and Igarashi sales and/or applications engineer to confirm feasibility in another application.


  1.  Small high power motors are subject to very fast temperature rises. Please take care not to apply excessive voltage or operation at stall or near stall for prolonged periods without first consulting Igarashi.

  2. Depending on motor operating condition (mounted, load, and environmental temperature), the motor might generate excessive heat. Take care not to burn yourself.

  3. DON'T block the motor shaft while electrical power is applied. Even a short-time lock-up may cause excess heat build-up resulting in thermal damage to the motor.

  4. Igarashi recommends to operate brushed DC-motors in the application at about 30% of projected motor stall torque at nominal conditions (voltage and room temperature) and the application has to minimize the time of powering the motor in a near stalled condition!

  5. Igarashi recommends not to operate brushed DC-motors in the application at no load or underload or external driven (open circuit generator operation). If necessary for the application this needs special investigation and may need design adjustment.

Critical Storage Conditions

  1. Exposure to very high/low temperature, extreme humidity, or an atmosphere with corrosive gas can damage components of the motor or cause a degradation of performance. Recommended environmental storage conditions:

    • Temperature +10 °C to +30 °C and relative humidity of 30% to 95%.

    • Warehousing for six months or longer (for motors with grease three months or longer), starting performance might be deteriorated. Oxidation to the carbon brush and commutator surfaces will occur when the motor is not operating (e.g. storage and transportation). This can cause an increase of electrical resistance. The amount of resistance change is relative to the level of temperature and humidity during non-operational time. Be aware that motor performance will be slightly affected when first running after a long time of no operation. After motor start up the brushes will clean the commutator and restore original performance.

  2. Atmosphere including fumigant (pesticides, etc.) and its gas can damage components of the motor.

  3. Atmosphere including gases generated by silicone, cyanic adhesives and halogen gas will cause permanent damage to motor components. Even in small quantities.

Hazardous environments

The degree of protection against corrosion on Igarashi motors is satisfactory only for normal environments. It is common for some metal components, such as the case, to have pre-plated steel in which the cut edges have bare metal and is susceptible to corrosion. If you have any concerns please get in contact with Igarashi.

Always remember that Igarashi application engineers are dedicated to solve problems of the application of our motors in new products and can assist our customer to find a solution to any problem which customer may encounter.

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