FAQ

A correct mounting of the tool is necessary to guarantee a long-lasting of the spindle bearings and to obtain a good surface finishing.

• before fixing the tool on the electrospidle carefully blow with compressed air the inside taper, the collet locking nut, the collet, and the tool.
• Clean them with mixed thinner oil (92%+8%) to remove the processing residual and if it is necessary use soft paper to clean.
• Fix the collet on the nut and check that it could turn freely.
• Insert them into the inside taper of the electrospindle and screw in the nut by hand.
• Insert the tool and check that it could move axially freely.
• Screw in the nut with the advised torque using the apposite wrench.
• Check the run out of the tool. If you can not check the run-out of the tool because of the cutters you can use a straight ground bar of the same diameter of the tool. Checking the run-out of the bar will give you information about the status of the collet and of the cone of the spindle. At this point, you must be sure that the tool is straight!! (From our experience this is not always true, the tool can be damaged)

We remind you that the life of the collet is not unlimited. You must check the collet status after many working hours.

Do not use inappropriate tools (i.e. tool with segeer, etc…)
If the tool length is larger than 80-100mm, use ultra-precise collets. (contact Teknomotor technical office for more information)
[email protected]

If it is not specified differently the motors can work in an environment in which there aren’t water or refrigerant jets used during machining. The motor can not work in a misty environment.

Air sealed motors are available for environments where water or refrigerant jets are present.
For more information call Teknomotor Technical Office.

This kind of shaft is available for manual tool change electrospindle and HF motor in accordance with DIN 6499/B collet:

• P-ER16 = Designed for collet ER16; available diameter: from 1 to 10 mm.
• P-ER20 = Designed for collet ER20; available diameter: from 2 to 13 mm.
• P-ER25 = Designed for collet ER25; available diameter: from 2 to 16 mm.
• P-ER32 = Designed for collet ER32; available diameter: from 2 to 20 mm.
• P-ER40 = Designed for collet ER40; available diameter: from 3 to 30 mm.

It is available also another kind of shafts for HF motors. (See the catalog). For custom-made shafts call Teknomotor Technical Office.

Every Model is marked by a letter that denotes the frame dimension. The “A” letter marks the shortest motor and the “D” letter the longest motor.

When the inverter is connected with the motor it must be remembered to modify some inverter parameters to allow the motor to work properly and not to be damaged.

Warning:

• feeding the motor with a wrong feed curve can irreparably damage the motor in a few seconds.
• the factory setting of every inverter must be modified to allow it to work with an HF motor/electrospindle.

Most important parameters:

• Base Frequency (point A): it is the frequency to which it corresponds the maximum voltage acceptable by the motor (base voltage). The factory setting of this parameter is usually 50Hz this parameter must be set equal to the base frequency of the motor (usually 100Hz, 200Hz, 300Hz, 400Hz depends on the motor type). The value of the base frequency of your motor is written on the nameplate or in the instruction sheet.
• Base Input Voltage: it is the maximum input voltage to which the motor can work. Generally, this value is 220V or 380V, it depends on the motor wiring.
• Max Frequency (point B): it is the maximum frequency to which the motor can work. It can correspond with the base frequency or it can be higher depending on the bearing type and on the balancing grade.
• Auto tuning functions: to avoid any damaging to the motor we suggest not to use the auto-tuning functions of your inverter but manually set up the inverter parameters with a linear [V; F] curve.

Warning: please refer to the inverter manufacturer manual to correctly install the inverter.

The HF motors and the electrospindle can be supplied with different types of plugs.
The connection of the power supply of the motor (220V or 380V) must be indicated by the customer in the order.

Two models are available:

• Plugs with die-cast aluminum cover
  Plugs with screw terminal. No particular instruments are required.
• Plugs with plastic cover
  The pins are clamped by a special instrument. This kind of tightening is faster than srew terminal.

When the order is placed it is fundamental to ask for the correct type of balancing to avoid any excessive vibration when the motor is coupled with the tool.
An incorrect match between tool and motor shaft causes vibrations which can compromise the finishing grade of the part as well as considerably reduce the motor life.

Half key balancing (HK):
this balancing method is usually associated with a one-slot tool. In this case, we have two asymmetrical and unbalanced rotors which will compensate each other when assembled together making a balanced system.

Full key balancing (FK):
this balancing method is usually associated with a two-slots tool. In this case, the tool is symmetrical and balanced and the motor shaft is balanced to compensate for the keyway protrusion. The matching of the two rotors will make a balanced system.

The main difference consists in the type of the load the motor can be subjected to, radial load for the HF motor, mixed load, or pure axial load for the electrospindle.
The electrospindle is moreover balanced with a lower grade (lower vibrations value) in comparison with HF motor because it is subjected to a process of dynamic balancing.
At last, the electrospindle allows faster rotational speed thanks to the better performance of the angular contact ball bearing compared with a deep groove bearing.

* the rpm values are indicative as they depend on the model.

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Warning:

• The choice of the correct correlation between the direction of rotation of the motor and the direction of the shaft thread is binding to guarantee the safety of the people involved with the job.
• A wrong correlation between the direction of rotation of the motor and the direction of the thread can cause the loosening of the locking nut. This can cause serious or fatal consequences for the operator.
• The correct correlation between the direction of rotation of the motor and the direction of the thread does not allow not to consider all the other security norms for the protection of the operators involved in the machine operations or maintenance.

• If the motor rotates clockwise the thread must be counterclockwise (left hand.)
• If the motor rotates counterclockwise the thread must be clockwise (right hand.)

The following table has been made with the purpose to summarize in brief the meaning of the codes delle sigle S1 and S6 (IEC 60034-1) and to allow the costumer to choose fastly the duty cycle he need and to correctly select it while filling the offer.
The codes S2 and S3 are reported just for a matter of completeness.
For more informations, we advice to consult the technical norm IEC 60034-1.* Unless otherwise specified, the total lasting of the cycle (S3 and S6) is of 10 minutes and the intermittence ratios (time with load/total cycle time) must be equal to one of the following values: 15%; 25%; 40%; 60%

Obviously, the continuous service S1 is the most burdensome, because, unlike the other three, does not previde a time of rest.
Under the load conditions S2; S3 and S6 can be applied greater loads then those permitted in a continuous cycle.

It describes the method to link the power and the speed of a motor according to the effective speed.
Reference is now made to the figure below relative to a linear [V; F] curve control.
The available data for the calculation can be found in the catalog; for each motor is declared Nominal power and Nominal speed (point A).

POWER OF THE MOTOR

From low speed until the nominal speed (point A), the power increases linearly as represented by the inclined blue line.
IIn this stretch the power can be calculated with this formula:

From point A to point B the Power is approximable nearly constant until reach maximum speed (point B) In this stretch, the power is obtained as follows:
$$ Power\ [kW] =Nominal\ Power\ [kW]$$

TORQUE OF THE MOTOR

From low speed until the nominal speed (A) the motor torque is equal to the nominal torque. From the point A to the point B the motor torque decreases as represented by the red curve in the figure below. The Nominal torque is calculated as follows:

$$ Nominal\ torque\ [Nm]\ =\ 9549\ x\ {Nominal\ power\ [kW]\ \over Nominal\ speed\ [RPM]}$$

Caution to the minimum functioning speed: for high-frequency motors exist a minimum speed of operation to ensure a proper ventilation of the motor with a continuous operation; this speed is usually at 6000 rpm. To be able to get off at lower speeds it is necessary to provide for the mounting of an increased fan diameter or an electric fan (in this case contact the technical office).

Figure: Power [W] and Torque [Nm] as a function of speed [rpm].

EXAMPLE OF ELECTROSPINDLE: ATC71 – A – ISO30 – SN

With this electrospindle we have a maximum power (S1) of 3.8 [kW] and a nominal speed of 12000 [rpm]. Under the nomial speed the motor generates a lower power than the nominal power and this can be seen in the example.

DATA:
Example of desired speed: 7800 [rpm];
Nominal power (S1): 3.8 [kW];
Nominal speed: 12000 [rpm].

$$ Power\ @\ 7800\ RPM = {3.8\ [kW]\ \over 12000\ [RPM]}\ x\ 7800\ [RPM]\ = 2.47\ [kW]$$

$$ Torque\ @\ 7800\ RPM\ = 9549\ x\ {3.8\ [kW] \over 12000\ [RPM]}\ =\ 3.0\ [Nm]$$

Example: green dots are the Power [kW] and the Torque [Nm] of working.

BOND BETWEEN SPEED AND FREQUENCY

Another useful formula to find speed [rpm] from frequency [Hz] and the number of pole pairs pp:
\[Speed\ [rpm] = {60 × frequency\ \over 2a}.\]