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    3.5 kW Air Cooled CNC Spindle Motor, 18000 rpm, ER25

    5 out of 5 based on 2 reviews | Write a review
    3.5 kW air cooled spindle motor with ER25 collet for CNC router, it features high speed of 18000 rpm and low noise, 1.68 Nm torque, three phase, operates at 380V 300Hz, long service life and strict quality control.
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    Delivery date: 6-12 days

    3.5 kW CNC spindle motor for sale at economical price, 18000 rpm speed, 1.68 Nm torque, 300Hz frequency, 3 phase 380V AC operating voltage, ER25 (φ3.175 mm - φ16 mm) collet.


    • Spindle motor with air cooling fan and ER25 collet ensures smooth running.
    • Fast response, strong overload capacity, low noise and high mechanical precision.
    • High quality 4 pcs bearings (7008Cx2 + 7002Cx2), runout off less than 0.01mm, tapered bore less than 0.005mm.
    • P4 grade ceramic ball bearings used as spindle bearing, which improves the service life under high speed revolution.
    • Lubricated with grease, which is resistant to 200 degrees high temperature.
    • Tight sealing and two-layer dustproof design.


    This series air-cooled electric spindle motors mainly match with variable frequency drives or engraving machines, CNC router machine, and used for high speed profiling, drilling, cutting, engraving and groove milling of wood, metal, plastics, foam, rubber and other materials.

    Note: The spindle motor and VFD shall be suitable with each other. The specifications and parameter settings of the VFD shall match the nominal parameters of the spindle motor. Otherwise, it will burn the spindle motor if the settings are not correct.


    Model STF47-82-3.5
    Matched VFD Model GK3000-4T0055G (7.5 hp three phase VFD)
    GK3000-CS0055G (7.5 hp 1-phase 220V to 3-phase 380V VFD)
    Power 3.5 kW
    Phase Three phase
    Speed 18000 rpm
    Voltage 3-phase 380V±10% AC
    Current 7.2A
    Frequency 300Hz
    Torque 1.68 Nm
    Number of Pole 2 poles
    Cooling Type Air-cooled
    Installation Method Horizontally or Vertically (When the motor is installed, the radial runout standard is required to be within 5um, and the chuck is generally 10um-15um.)
    Lubrication Grease
    Thermal Class Class F
    Protection Class IP50
    Certification CE
    Warranty Bearings for half a year, other parts for one year
    Joint of Nose ER25 (φ3.175 mm - φ16 mm)
    Bearings Type 7008C P4*2 & 7002C P4*2
    Application Woodworking & Plastic
    Weight 8.5 kg
    PDFDownload Attachments 3.5kW Air Cooled Spindle Motor CAD Drawings



    3500W Air Cooled CNC Spindle Motor 18000rpm Details

    Tips: How to Select a Right Spindle Motor?

    The spindle motor is an important component of woodworking engraving machine. The quality of the spindle motor directly affect the processing speed and accuracy of the engraving machine. How to select high-quality spindle motor is very important. ATO summarizes the main points of woodworking engraving machine spindle selection for the reference of users:

    1. If we pursue the efficiency of woodworking engraving machine, we should not only have a high speed, but also a large amount of knives. For example, when processing solid wood, we need a spindle motor with a power of more than 3kW.

    2. Whether the spindle motor of woodworking engraving machine adopts high-precision bearings or not, if it does not use high-precision bearings, the performance is that the spindle motor overheated after long-term high-speed rotation, which affects the service life of the spindle motor.

    3. Whether the spindle of woodworking engraving machine rotates at different speeds, especially at high speeds, the sound is uniform and harmonious.

    4. Whether the radial force of the principal axis of woodworking engraving machine is applied. The main reference is whether the material with hard texture can be cut at high speed. Some spindle motors can only cut hard materials at very low speed, otherwise the performance of the motor will be seriously lost, which will affect the accuracy of the spindle after a period of time, or even cause faults.

    Safety Tips for Using ATO CNC Spindle Motors

    1. The electric spindle motor and VFD shall be suitable with each other. The specifications and parameter settings of the VFD shall match the nominal parameters of the spindle motor, and it will burn the spindle motor if the settings are not correct.

    2. Before using water-cooled spindle motor, it shall ensure that cooling cycle system works normally and the running under no cooling conditions is prohibited. The volume of cooling water is calculated as per 1 liter/minute, the minimum flow of cooling water is not less than 5 liter/minute, cooling water pipe and the nozzle shall be connected reliably and there is no leakage.

    3. The cooling liquid shall be clean and free of grease and the temperature shall be within 5-30℃. The cooling medium shall carry out force cooling when the ambient temperature is higher than 30℃. The precision lathe requires the cooling liquid with a constant temperature of 20 +/-2℃.

    4. During storage and transport of the spindle motor, the status of high-speed grease inside the bearing will change. The user shall run it at a low speed first by starting from the lowest speed of the spindle motor for 30 minutes and then 20 minutes for every 3000 rounds. Otherwise there will have abnormal sound, noise, heat and other phenomena, which will affect the bearing life if the spindle motor is started directly at a high speed. During long term storage, the spindle motor shall run (at low speed) for 15-30 minutes once a week at last.

    5. Collet, nut and inner taper hole shall be washed clean when installing blades on the spindle motor in order to avoid any impact on the precision. The blade handle shall be inserted into the collet more than 15mm.

    6. For daily machining, the spindle motor shall be warmed up, run for 15-20 minutes when the machining speed is reached and then performs precise machining. It is better to stop the spindle motor for two hours every day in order to recover its mechanical fatigue and prolong its life time.

    7. No knocking the end cover of the spindle motor. No hammering the collet and blade head when removing blades. No shocking or colliding during transport, storage and using, especially the end of the spindle motor.

    8. The spindle motor shall run in designated direction.

    9. The spindle motor shall be installed and fixed according to the relevant drawings and instructions.

    10. The temperature shall be within 22-25℃ if water cooling machine is used.

    11. The spindle motor adopts vapor lock and the gas source shall not be used until it has passed oil-water separator and dry filter. The air pressure is 0.2-0.25Mpa and the filtering precision is 5μm, otherwise there will cause damages to the bearing.

    Existing reviews of 3.5 kW Air Cooled CNC Spindle Motor, 18000 rpm, ER25
    Good value, works as it is advertised
    It was perfect. It's small size and light weight made it easy to operate. Spindle and VFD work very well. Overall I'm very satisfied with the performance of the spindle.
    From: zzt | Date: 26/04/2022
    Was this review helpful? Yes No (0/0)
    Nice spindle motor
    Very smooth, nicely machined and professional looking. Running at about 3600 RPM, this air cooled spindle motor is quieter than the pond pump that circulates the coolant. It is very quiet, to the point where you can barely hear it.
    From: Graeme Rand | Date: 05/01/2020
    Was this review helpful? Yes No (0/0)
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