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    3.7 kW Water Cooled CNC Spindle Motor, 24000 rpm, ER20

    5 out of 5 based on 2 reviews | Write a review
    3 phase 3.7 kW spindle motor with 24000 rpm high speed, 10A at 380V AC 400Hz, ER20 collet, φ100mm diameter, stable performance and high precision bearing. Water-cooled spindle motor is designed for wood carving CNC machine.
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    Delivery date: 6-12 days

    3.7 kW water cooled CNC spindle motor at fair price, 24000 rpm speed, 1.45 Nm torque, 400Hz frequency, 3 phase 220V/380V AC operating voltage, ER20 (φ3.175 mm - φ13 mm) collet.


    • Spindle motor with superior durability ER20 collet ensures smooth running.
    • Fast response, strong overload capacity, low noise and high mechanical precision.
    • High quality 3 pcs bearings (7005Cx2 + 7003Cx1), 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 water 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 STZ100-3.7-ER20
    Power 3.7 kW
    Diameter φ100 mm
    Phase Three phase
    Speed 24000 rpm
    Voltage 3-phase 380V±10% AC 3-phase 220V±10% AC
    Current 8A 10A
    Matched VFD Model GK3000-4T0055G (7.5 hp three phase VFD) GK3000-4T0055G (7.5 hp three phase VFD)
    Frequency 400Hz
    Torque 1.45 Nm
    Number of Pole 2 poles
    Cooling Type Water-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 ER20 (φ3.175 mm - φ13 mm)
    Bearings Type 7005C P4*2 & 7003C P4*1
    Application Woodworking & Plastic
    Weight 9 kg
    PDFDownload Attachments 3.7 kW Water Cooled Spindle Motor CAD Drawings



    3700W Water Cooled CNC Spindle Motor Details

    Tips: 3 Control Mode of Spindle Motor in CNC Machine

    In CNC machine tool processing, the spindle motor mainly has three control methods: Ordinary frequency conversion control, vector control and direct torque control.

    Ordinary frequency conversion is scalar drive and control, and its drive control characteristic is constant torque drive, and the output power is proportional to the speed. The dynamic performance of ordinary frequency conversion control is not ideal, the control performance is not good at low speed, the output power is not stable enough, and it does not have the C-axis function. But the price is cheap, the structure is simple, and it is generally used for grinders and ordinary high-speed milling machines.

    The vector control technology imitates the control of a DC motor, oriented by the rotor magnetic field, and realizes the drive and control by the method of vector transformation, which has good dynamic performance. The vector control drive has a large torque value when it is just started, and the spindle motor itself has a simple structure and small inertia, so the starting acceleration is large, and the allowable limit speed can be reached instantaneously after starting. This kind of driver has two kinds of open loop and closed loop. The latter can realize position and speed feedback, not only has better dynamic performance, but also can realize C-axis function; while the former has a slightly worse dynamic performance and does not have C-axis function, but the price is cheaper.

    Direct torque control is another new type of high-performance AC speed control technology developed after vector control technology. Its control idea is novel, the system structure is simple and clear, and it is more suitable for the drive of high-speed electric spindles and can meet the requirements of high-speed spindle motors. The dynamic and static characteristics of high speed, wide speed range, high speed and instant stop have become a hot technology in the field of AC drive.


    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 least.

    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 3.7 kW Water Cooled CNC Spindle Motor, 24000 rpm, ER20
    Great water cooled spindle motor at lower price!
    This 3.7kw water cooled CNC spindle motor is super quiet and works great. The spindle works great so far, I'd recommend this to anybody who needs it!
    From: Guthrie | Date: 25/05/2022
    Was this review helpful? Yes No (0/0)
    High quality 3.7kW water cooled CNC spindle motor
    This 3.7kw water cooled CNC spindle motor works well with VFD. There is no doubt that it can run for more than 4 hours without overheating, and it can be engraved on copper and brass without any problems.
    From: Brandy | Date: 02/09/2021
    Was this review helpful? Yes No (0/0)
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