Unlike traditional torque motors, TK units have both high torque and high speed capability and thus operate seamlessly both as spindle and rotary table motors.
The rotors use special Phase manufactured magnets with minimized loss factor allowing high speed operation with a thin isotropic rotor.
TK motors are three phase, rare earth (Iron Neodymium Boron) permanent magnet units and reach the highest continuous and peak torque density available today, together with high speed and flux control ability over a constant power range up to 10:1.
TK Torque Motors consist of stator and rotor units supplied separately suitable for direct mounting inside the machine structure.
All rotors are rigid units with mechanical, glue free magnet retention, preloaded carbon fiber sleeve for safe operation even at very high speed.
Rotor are often semi custom units to allow direct coupling to bearings, encoders, brakes.
Customized frames with integral cooling or even partial machine subassemblies with bearings and encoders are manufactured on request based on the standard frameless magnetic designs available.
| Torque Motor code | Stack [mm] | L tot.[mm] | Øout [mm] | Øin [mm] | Torque (Water Cooled) [Nm] | Torque (Air Cooled)[Nm] | Peak Torque [Nm] |
Nominal Speed (rpm) | Max Speed (rpm) |
| TK.085 | 50 | 110 | 96 | 44 | 7,30 | 3,70 | 24,10 | 5000 | 18000 |
| 100 | 160 | 96 | 44 | 16,20 | 8,10 | 48,20 | |||
| 150 | 210 | 96 | 44 | 25,40 | 12,70 | 72,30 | |||
| 200 | 260 | 96 | 44 | 34,70 | 17,40 | 96,40 | |||
| TK.110 | 50 | 125 | 121 | 43 | 12,50 | 6,30 | 33,20 | 5000 | 20000 |
| 100 | 175 | 121 | 43 | 26,90 | 13,50 | 66,30 | |||
| 150 | 225 | 121 | 43 | 41,60 | 20,80 | 99,50 | |||
| 200 | 275 | 121 | 43 | 56,30 | 28,20 | 132,70 | |||
| TK.120 | 50 | 125 | 134 | 54 | 21,90 | 11,00 | 47,50 | 5000 | 15000 |
| 100 | 175 | 134 | 54 | 48,20 | 24,10 | 95,10 | |||
| 150 | 225 | 134 | 54 | 75,10 | 37,60 | 142,60 | |||
| 200 | 275 | 134 | 54 | 102,40 | 51,20 | 190,00 | |||
| TK.164 | 50 | 125 | 173 | 76 | 48,30 | 24,10 | 93,50 | 4000 | 10000 |
| 100 | 175 | 173 | 76 | 104,70 | 52,30 | 187,00 | |||
| 150 | 225 | 173 | 76 | 162,10 | 81,10 | 280,40 | |||
| 200 | 275 | 173 | 76 | 219,90 | 110,00 | 374,00 | |||
| 300 | 375 | 173 | 76 | 336,00 | 168,00 | 560,90 | |||
| TK.188 | 50 | 140 | 202 | 80 | 34,80 | 17,40 | 119,50 | 6000 | 28000 |
| 100 | 90 | 202 | 80 | 79,10 | 39,50 | 238,90 | |||
| 150 | 240 | 202 | 80 | 125,80 | 62,90 | 358,40 | |||
| 200 | 290 | 202 | 80 | 173,60 | 86,80 | 477,80 | |||
| 300 | 390 | 202 | 80 | 270,50 | 135,20 | 716,80 | |||
| TK.195 | 50 | 160 | 207 | 76 | 49,50 | 24,80 | 93,50 | 2000 | 15000 |
| 100 | 210 | 207 | 76 | 108,69 | 54,30 | 187,00 | |||
| 150 | 260 | 207 | 76 | 169,20 | 84,60 | 280,40 | |||
| 200 | 310 | 207 | 76 | 230,20 | 115,00 | 374,00 | |||
| 300 | 410 | 207 | 76 | 352,70 | 176,40 | 560,90 | |||
| TK.220 | 50 | 170 | 240 | 110 | 75,60 | 37,80 | 159,00 | 3000 | 14000 |
| 100 | 220 | 240 | 110 | 172,40 | 86,20 | 318,10 | |||
| 150 | 270 | 240 | 110 | 274,40 | 137,20 | 477,10 | |||
| 200 | 320 | 240 | 110 | 378,70 | 189,30 | 636,20 | |||
| 300 | 420 | 240 | 110 | 590,10 | 295,10 | 954,30 | |||
| TK.240 | 50 | 135 | 249 | 142 | 111,20 | 55,60 | 216,50 | 3000 | 8000 |
| 100 | 185 | 249 | 142 | 240,00 | 120,00 | 433,00 | |||
| 150 | 235 | 249 | 142 | 371,30 | 185,60 | 649,40 | |||
| 200 | 285 | 249 | 142 | 465,90 | 251,60 | 865,90 | |||
| TK.270 | 50 | 140 | 282 | 160 | 112,30 | 56,20 | 282,70 | 3000 | 8000 |
| 100 | 190 | 282 | 160 | 253,00 | 126,50 | 565,50 | |||
| 150 | 240 | 282 | 160 | 399,30 | 199,60 | 848,20 | |||
| 200 | 290 | 282 | 160 | 547,70 | 273,90 | 1.131,00 | |||
| TK.310 | 50 | 120 | 310 | 198 | 215,60 | 107,80 | 373,90 | 500 | 3000 |
| 100 | 170 | 310 | 198 | 475,90 | 238,00 | 748,00 | |||
| 150 | 220 | 310 | 198 | 743,30 | 371,70 | 1.121,80 | |||
| 200 | 270 | 310 | 198 | 1.013,00 | 506,60 | 1.495,70 | |||
| TK.340 | 50 | 145 | 358 | 190 | 242,00 | 121,00 | 407,20 | 2000 | 6000 |
| 100 | 195 | 358 | 190 | 547,20 | 273,60 | 814,30 | |||
| 150 | 245 | 358 | 190 | 864,70 | 432,40 | 1.221,50 | |||
| 200 | 295 | 358 | 190 | 1.186,90 | 593,50 | 1.628,60 | |||
| 300 | 395 | 358 | 190 | 1.837,00 | 918,50 | 2.442,90 | |||
| TK.370 | 50 | 140 | 380 | 268 | 271,70 | 135,90 | 636,20 | 1000 | 4000 |
| 100 | 190 | 380 | 268 | 604,50 | 302,20 | 1.272,30 | |||
| 150 | 240 | 380 | 268 | 947,40 | 473,70 | 1.908,50 | |||
| 200 | 290 | 380 | 268 | 1.294,00 | 647,00 | 2.544,70 | |||
| 300 | 390 | 380 | 268 | 1.991,40 | 995,70 | 3.817,00 | |||
| TK.450 | 50 | 170 | 465 | 320 | 468,20 | 234,10 | 916,10 | 1000 | 3000 |
| 100 | 220 | 465 | 320 | 1.033,70 | 516,90 | 1.832,20 | |||
| 150 | 270 | 465 | 320 | 1.613,00 | 806,50 | 2.748,30 | |||
| 200 | 320 | 465 | 320 | 2.196,90 | 1.098,40 | 3.664,40 | |||
| TK.485 | 50 | 145 | 485 | 345 | 544,00 | 213,00 | 1.068,00 | 1000 | 2000 |
| 100 | 195 | 485 | 345 | 1.197,00 | 500,00 | 2.136,00 | |||
| 150 | 245 | 485 | 345 | 1.858,00 | 802,00 | 3.204,00 | |||
| 200 | 295 | 485 | 345 | 2.521,00 | 1.110,00 | 4.272,00 | |||
| TK.540 | 50 | 145 | 548 | 400 | 712,80 | 356,40 | 1.431,40 | 400 | 1500 |
| 100 | 195 | 548 | 400 | 1.547,50 | 773,80 | 2.862,80 | |||
| 150 | 245 | 548 | 400 | 2.397,40 | 1.198,70 | 4.294,20 | |||
| 200 | 295 | 548 | 400 | 3.252,00 | 1.626,00 | 5.725,60 | |||
| TK.570 | 50 | 115 | 578 | 450 | 745,40 | 372,70 | 1.767,10 | 400 | 1500 |
| 100 | 165 | 578 | 450 | 1.673,00 | 836,50 | 3.534,30 | |||
| 150 | 215 | 578 | 450 | 2.632,50 | 1.316,20 | 5.301,40 | |||
| 200 | 265 | 578 | 450 | 3.603,60 | 1.801,80 | 7.068,60 | |||
| TK.795 | 50 | 160 | 815 | 640 | 1.631,10 | 815,50 | 3.365,40 | 200 | 800 |
| 100 | 210 | 815 | 640 | 3.781,20 | 1.890,60 | 6.730,70 | |||
| 150 | 260 | 815 | 640 | 6.063,60 | 3.031,80 | 10.096,10 | |||
| 200 | 310 | 815 | 640 | 8.402,10 | 4.201,10 | 13.461,40 | |||
| TK.1150 | 50 | 190 | 1210 | 908 | 3.495,00 | 1.785,00 | 6.789,00 | 100 | 400 |
| 100 | 240 | 1210 | 908 | 7.996,00 | 4.281,00 | 13.577,00 | |||
| 150 | 290 | 1210 | 908 | 12.696,00 | 6.952,00 | 20.366,00 | |||
| 200 | 340 | 1210 | 908 | 17.457,00 | 9.695,00 | 27.155,00 | |||
| TK.1340 | 50 | 190 | 1420 | 1100 | 4.542,80 | 2.271,40 | 9.842,30 | 100 | 400 |
| 100 | 240 | 1420 | 1100 | 10.639,40 | 5.319,70 | 19.684,60 | |||
| 150 | 290 | 1420 | 1100 | 17.147,10 | 8.573,50 | 29.526,90 | |||
| 200 | 340 | 1420 | 1100 | 23.831,50 | 11.915,70 | 39.369,20 | |||
| TK.1700 | 50 | 190 | 1770 | 1420 | 8.113,80 | 4.056,90 | 15.946,80 | 100 | 300 |
| 100 | 240 | 1770 | 1420 | 18.951,20 | 9.475,60 | 31.893,50 | |||
| 150 | 290 | 1770 | 1420 | 30.480,20 | 15.240,10 | 47.840,30 | |||
| 200 | 340 | 1770 | 1420 | 42.301,80 | 21.150,90 | 63.787,00 | |||
| TK.2000 | 50 | 260 | 2085 | 1700 | 8.587,40 | 4.293,70 | 23.004,10 | 100 | 300 |
| 100 | 310 | 2085 | 1700 | 20.713,90 | 10.356,90 | 46.008,20 | |||
| 150 | 360 | 2085 | 1700 | 34.103,80 | 17.051,90 | 69.012,30 | |||
| 200 | 410 | 2085 | 1700 | 48.132,40 | 24.066,20 | 92.016,40 | |||
| TK.3080 | 50 | 260 | 3170 | 2760 | 24.318,60 | 12.159,30 | 51.035,20 | 100 | 250 |
| 100 | 310 | 3170 | 2760 | 57.331,50 | 28.665,80 | 102.070,30 | |||
| 150 | 360 | 3170 | 2760 | 92.790,20 | 46.395,10 | 153.105,50 | |||
| 200 | 410 | 3170 | 2760 | 129.340,00 | 64.670,00 | 204.140,70 |
TK motors consist of:
A three phase stator, wound and impregnated (3 dips, preferred solution for high thermal cycling), or vacuum encapsulated in super high thermal conductivity compound (for low surface temperature operation), which is either built into a thin steel microframe, cylindrical, or into a metallic frame carrying the cooling chambers and coupling O-Rings on the outside and a set of tapped holes on one side (Squid type).
The microframe units are ground to h7 tolerance on the outside diameter and are machined parallel on the two stack sides. This construction is intended for interference fit or axial pressure locking.
The microframe technology maximizes the usage of space in the assembly and requires the machine body to carry the cooling cavities on the inside. It requires some care in the design of the application but results in the highest space and power density today possible.
Alternately, the SQUID frame is much simpler to use and only requires a cylindrical cavity, while motor assembly and fastening s just through a set of screws. The achieved torque density is slightly inferior to the microframe due to the radial size of the frame.
The insulation system of the motors is rated Class H (magnet wire: Class C) with reinforced insulation specifically designed for the high DV/dt typical of 600 Vdc servo drive application; the windings are equipped with three PTC sensors for protection and a KTY 84 linear temperature probe for process monitoring.
The star point of the winding is also generally available for filtering purposes. All windings are factory tested for insulation 4.5 kVdc to ground and 3.5 kVdc phase to phase, far in excess of regulation requirements.
A Permanent Magnet Rotor, with tubular, isotropic base shape, which carries the magnets on the outside periphery, protected by a preloaded carbon fiber (up to 150 m/sec) ring.
The magnets are generally high temperature, high energy FeNdB sintered magnets, Phase Motion Control manufactured with a special patented technology. They are designed for the maximum class temperature and are virtually impossible to demagnetise except in case of drive failure or improper operation. If continuous exposure to oil is forecast, special oil resistant magnets can be specified.
The rotor may be fastened on the shaft either by interference fit or by an array of axial bolts. The latter construction is preferred for high torque, low speed applications such as rotary tables. In general, the rotor inside profile is customised to fit with the needs of the machine provided the required profile is compatible with the maximum hole required by the magnetic field, and specified in the accompanying technical sheets.
For proper operation, the motors need a position sensor on the shaft (not supplied) both for field orientation and for position/speed control.
The rotor is permanent magnet type and has no primary losses, so that no rotor cooling is needed in principle. However, the inverter chopper frequency must be set high enough to ensure that the ripple current, pk-pk is less than 20% of the nominal rms current to avoid the insurgency of unacceptable, and dangerous, stray rotor loss.
Customized frames with integral cooling or even partial machine subassemblies with bearings and encoders are manufactured on request based on the standard frameless magnetic designs available.
The rotors are supplied not balanced; high speed operation requires dynamic balancing when assembled on the application shaft.
Thin ring, large diameter motors for high torque, low speed (torque motors)
Typical applications:
In all these applications, direct drive eliminates play and removes the need of an accurate mechanical gearbox, which in turn would limit the accuracy and the dynamic performance of the system. Mechanical brakes-dividers are unnecessary. The table accuracy is the accuracy of the encoder system. The system is thus extremely simple, flexible and reprogrammable.
The removal of the transmission system and of its backlash and elasticity results in control bandwidth up to 250 Hz, so that a positioning cycle can be completed with great accuracy within a few msec with advantage on the machine cycle time. To ensure adequate servo performance in direct drive high accuracy, high stiffness applications such as indexing and rotary tables in NC machine tools, the sensor must be sinusoidal so that the drive may interpolate the actual position with a resolution at least ten times greater than the required accuracy. Additionally, the sensor fastening or spring mount must have intrinsic resonance frequency above 2000 Hz not to limit the overall system performance.
Spindle motors for mills and lathes
long and thin motors, brushless with flux control ability, medium to high speed, high power density, suitable for heavy machining or control of large inertia loads for spool winding/unwinding. The TK motors have currently the highest power density and allow the manufacture of electrospindles with torque rating hiterto unattainable, in the range of several thousand Nm while reaching high speeds in the thousands of rpm. Spindle type motors are anyway high performance servo motors so another emerging application area is very short cycle actuation. Recent application are in direct drive of the ram of high speed turret punching press with stroke rates in excess of 300 strokes/min, or fast, heavy indexing in wire frame welding machines.
Typical applications:
Tube motors, small diameter, for multiple spindle units
| Standard size of terminal cables vs nominal motor current | |
| PTFE insulation, 2500 Vac, L=500 mm | |
| Nominal current | Wire size |
| In < 15 Arms | 1.22 mmq = AWG 16 |
| 15 Arms <= In< 25 Arms | 2.97 mmq = AWG 12 |
| 25 Arms <= In< 45 Arms | 8.6 mmq = AWG 8 |
| 45 Arms <= In< 82 Arms | 15 mmq |
| 82 Arms <= In< 110 Arms | 25 mmq |
| 110 Arms<=In< 200 Arms | 50 mmq |
First, define the technical feasibility of the application. In general, all motors share the same physical limitation, that is, the ability to generate “airgap thrust”, i.e. a sideways thrust between stator and rotor which is linear thrust in linear motor, and becomes a torque when the motor is round. The amount of thrust per unit area depends on motor technology but is fundamentally limited by the properties of the materials (magnets, copper, steel) used in the motors. PM technology offers the highest specific thrust available today, and this value is gradually increased as the technology improves. Many factors (cooling conditions, size, airgap thickness, linear speed etc.) affect this value which should only be used as a rough guideline. Tk rotary motors and Wave linear motors are characterised by a peak thrust around 8000 N/m2, continuous thrust with water cooling ~ 5500 N/m2.
Large rings with very limited axial length are the most efficient solution for high torque low speed applications, and they have the additional advantage of not needing separate bearings as they can be generally carried by the same bearings of the load. However, inertia scales with the cube of diameter, so where the inertia is the dominant load, long and thin motors are more appropriate. A typical example is the direct drive of the ram of high speed punch presses, in which motion is reversed over 300 times/min, or in high speed flying shears; in this case, tubular, water cooled TK motors provide the highest performance solution.
Spindle drives generally demand both high torque and high speed but the diameter is generally restricted, so they tend to be long and thin. Airgap hole diameter to length ratios up to 1:3 are routinely manufactured. In this case, the Phase PM magnet technology allows the manufacture of extremely thin stators and rotors which are particularly useful in multispindle applications.
Spindle PM motors manufactured with the high frequency Phase magnetic technology can operate both in constant torque and constant power mode. The constant power range, depending on the type, can exceed 10:1 although this is generally limited by the ability of the drive selected to control a deep deflux range.
When compared to AC Induction spindle motors, the PM motor design offers:
In the Phase TK technology, there is no fundamental physical difference between torque motors and spindle motors; they have the same smoothness and high bandwidth necessary for direct drive indexing and contouring operation, so that milling and turning operations on the same motor are now possible.
There is, however, a fundamental difference between PM and induction spindle drives. In the induction technology, power is used to magnetize the motor (at low speed, high torque) thus resulting in limited output torque available; flux reduction is easily obtained by just reducing the magnetizing current.
Thus the motor is “hot” at max load, and “cool” at no load. PM motors, conversely, derive the field from high energy permanent magnets, so that no power is required to build the motor field and more power can be devoted to torque generation. When the flux must be reduced, however, power must be applied just to lower the field so that PM motors at high speed need some current even at no load.
A typical power and torque curve versus speed is shown in Fig. 1 for a combined torque/spindle motor with 570 mm diameter, 100 mm axial length; in Fig. 2, the motor temperature at no load and full loads are displayed. It can be observed that above the “knee speed” i.e. the speed of transition between constant torque and constant power operation, the motor temperature becomes progressively independent of motor load.
Another useful feature of PM technology is the ability to operate with a wide airgap, up to several millimetres in the larger motors. This feature can be useful in machines with important deformations, such as plastic injection press or impact hammers. As a standard the airgap is in the order of 1 mm, radial, and this generally enables designs in which the motor rides on the machine supports without need of separate bearings.
The magnetic flux in the rotor generates radial attraction forces.
These are perfectly balanced only if the rotor sits in the center of the stator, and increase with eccentricity. In practice, this is equivalent to a “negative stiffness” which must be compensated by a much higher positive stiffness in the bearing system. The attraction data can be supplied on demand, the order of magnitude is shown in the graph in Fig. 3, for a 1000 Nm, 370 mm diameter, 105 mm long torque motor with a 1 mm radial airgap.
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