Experience Wittipedia . . . your one-stop shop for all relevant motion and technical information. Browse through the articles below or click on a letter to narrow your search. Want something that isn't here? Drop us an email...

A     B     C     D     E     F     G      H     I      J     K      L     M      N     O     P     Q     R     S      T     U       V     W      X     Y    Z

A

Acceleration torque (T2B)
The acceleration torque T2B is the maximum permissible torque that can briefly be transmitted at the output by the gearhead afteR < 1000/h cycles. For > 1000/h cycles, the impact factor must be taken into account. T2B is the limiting parameter in cyclic operation.

Adapter plate
WITTENSTEIN alpha uses a system of standardized adapter plates to connect the motor and the gearhead, making it possible to mount a WITTENSTEIN alpha gearhead to any desired motor without difficulty.

Angular minute
A degree is subdivided into 60 angular minutes (= 60 arcmin = 60´). In other words, if the torsional backlash is specified as 1 arcmin, for example, the output can be turned 1/60°. The repercussions for the actual application are determined by the arc length: b = 2 · · r · ° / 360°. A pinion with a radius r = 500 mm on a gearhead with standard torsional backlash         jt = 3‘ can be turned b = 0.4 mm.

Axial force (F2AMax)
In the case of SP+/LP+/SPK+, the axial force F2AMax acting on a gearhead runs parallel to its output shaft. On a TP+, the force runs perpendicular to its output shaft. It may be applied with axial offset via a lever arm y2 under certain circumstances, in which case it also generates a bending moment. If the axial force exceeds the permissible catalogue values, additional design features (e.g. axial bearings) must be implemented to absorb these forces.

 

B

Bushing
If the motor shaft diameter is smaller than the clamping hub, a bushing is used to compensate the difference in diameter.

 

C

Clamping hub
The clamping hub ensures a frictional connection between the motor shaft and gearhead. A bushing is used as the connecting element if the motor shaft diameter is smaller than that of the clamping hub.

Continuous operation (S1)
Continuous operation is defined by the duty cycle. If the duty cycle is greater than 60% or longer than 20 minutes, this qualifies as continuous operation. See also Operating modes.

Control Loading System
This system uses active or passive technology to provide pilots with realistic flight control forces in a flight simulator or training device. Learn more at Wikipedia . . .

Cyclic operation (S5)
Cyclic operation is defined via the duty cycle. If the duty cycle is less than 60% and shorter than 20 minutes, it qualified as cyclic operation. See also Operating modes.

cymex®
cymex® is the calculation software developed by our company for dimensioning complete drive trains. We can also provide training to enable you to make full use of all the possibilities provided by the software.

 

D

Degree of protection (IP)
The various degrees of protection are def ned in DIN EN 60529 “Degrees of protection offered by enclosure (IP code)”.
The IP degree of protection (IP stands for International Protection) is represented by two digits. The first digit indicates
the protection against the ingress of impurities and the second the protection against the ingress of water.

Duty cycle (ED)
The duty cycle ED is determined by one cycle. The times for acceleration (tb), constant travel if applicable (tc) and deceleration (td) combined yield the duty cycle in minutes. The duty cycle is expressed as a percentage with inclusion
of the pause time te.

 

 

E

Efficiency (n)
Efficiency [%] n is the ratio of output power to input power. Power lost through friction reduces efficiency to less than 1 or 100 %.
n = Pout / Pin = (Pin - Plost) / Pin
WITTENSTEIN alpha always measures the efficiency of a gearhead during operation at full load (T2B). If the input power
or torque are lower, the efficiency rating is also lower due to the constant no-load torque. Power losses do not increase as a result. Speed also has an effect on efficiency, as shown in the example diagram above.

Emergency stop torque (T2Not)
The emergency stop torque [Nm] T2Not is the maximum permissible torque at the gearhead output and must not be reached more than 1000 times during the life of the gearhead. It must never be exceeded.

 

H

High Speed (MC)
The High Speed version of our SP+ gearhead has been specially developed for applications in continuous operation at
high input speeds, e.g. as found in the printing and packaging industries.

High Torque (MA)
The High Torque version of our TP+ gearhead has been specially developed for applications requiring extremely high
torques and maximum rigidity.
MA = High Torque
MC = High Speed
MF = standard versions of our WITTENSTEIN alpha servo gearheads

Hysteresis curve
The hysteresis is measured to determine the torsional rigidity of a gearhead. The result of this measurement is known as the hysteresis curve.

IIf the input shaft is locked, the gearhead is loaded with a torque that increases continuously up to T2B and is then relieved at the output in both directions. The torsional angle is plotted against the torque. This yields a closed curve from which the torsional backlash and torsional rigidity can be calculated.

 

I

Impact factor (fs)
The maximum permissible acceleration torque during cyclic operation specified in the catalog applies for a cycle rate less
than 1000/h. Higher cycle rates combined with short acceleration times can cause vibrations in the drive train. Use the load factor fs to include the resulting excess torque values in calculations. The impact factor fs can be determined with reference to the curve. This calculated value is multiplied by the actual acceleration torque T2b and then compared with the maximum permissible acceleration torque T2B. (T2b · fs = T2b, fs < T2B)

 

J

Jerk
Jerk is derived from acceleration and is defined as the change in acceleration within a unit of time. The term impact is
used if the acceleration curve changes abruptly and the jerk is infinitely large.

 

L

Lateral force (FR)
Lateral force is the force component acting at right angles to the output shaft with the SP+/LP+/SPK+ or parallel to
the output flange with the TP+. It acts perpendicular to the axial force and can assume an axial distance of x2 in relation
to the shaft nut with the SP+/LP+) or shaft flange with the TP+, which acts as a lever arm. The lateral force produces
a bending moment (see also axial force).

 

M

Mass moment of inertia (J)
The mass moment of inertia J is a measurement of the effort applied by an object to maintain its momentary condition
(at rest or moving).

Mesh frequency (fz)
The mesh frequency may cause problems regarding vibrations in an application, especially if the excitation frequency corresponds to the intrinsic frequency of the application. The mesh frequency can be calculated for all SP+, TP+ , LP+ and alphira® gearheads using the formula fZ = 1.8 · n2 [rpm] and is therefore independent of the ratio if the output speed is the same. If it does indeed become problematic, the intrinsic frequency of the system can be changed or another gearhead (e.g. hypoid gearhead) with a different mesh frequency can be selected.

 

N

No load running torque (T012)
The no load running torque T012 is the torque which must be applied to a gearhead in order to overcome the internal friction; it is therefore considered lost torque. The values specified in the catalog are calculated by WITTENSTEIN alpha at a speed of n1 = 3000 rpm and an ambient temperature of 20 °C.

Nominal torque (T2N)
The nominal torque [Nm] T2N is the torque continuously transmitted by a gearhead over a long period of time, i.e. in continuous operation (without wear).

 

O

Operating modes (continuous operation S1 and cyclic operation S5)
When selecting a gearhead, it is important to consider whether the motion profile is characterized by frequent acceleration and deceleration phases in cyclic operation (S5) as well as pauses, or whether it is designed for continuous operation (S1), i.e. with long phases of constant motion.

Operating noise (LPA)
Low noise level LPA is a factor of growing importance for environmental and health reasons. WITTENSTEIN alpha has succeeded in reducing the noise of the new SP+ gearheads by another 6 dB(A) over the former SP units (i.e. sound reduced to one quarter). Noise levels are now currently 64 - 70 dB(A) depending on the size of the gearhead. The gear ratio and speed both affect the noise level. The relationships are demonstrated in the following trend graphs. As a general rule: A higher speed means a higher noise level, while a higher ratio means a lower noise level. The values specified in our catalog relate to gearheads with the ratio i = 5 at a speed of n = 3000 rpm.

 

P

Positioning accuracy
The positioning accuracy is determined by the angular deviation from a setpoint and equals the sum of the torsional angles due to load (torsional rigidity and torsional backlash) and kinetics (synchronization error) occurring simultaneously in practice.

 

R

Ratio of mass moment of inertia ( = Lambda)
The ratio of mass moment of inertia is the ratio of external inertia (application side) to internal inertia (motor and gearhead side). It is an important parameter determining the controllability of an application. Accurate control of dynamic processes becomes more difficult with differing mass moments of inertia and as becomes greater. WITTENSTEIN alpha recommends that a guideline value of < 5 is maintained. A gearhead reduces the external mass moment of inertia by a factor of 1/ i .

Ratio (i)
The gear ratio i indicates the factor by which the gearhead transforms the three relevant parameters of motion (speed, torque and mass moment of inertia). The factor is a result of the geometry of the gearing elements (Example: i = 10).

 

S

Speed (n)
Two speeds are of relevance when dimensioning a gearhead: the maximum speed and the nominal speed at the input. The maximum permissible speed n1Max must not be exceeded because it serves as the basis for dimensioning cyclic operation. The nominal speed n1N must not be exceeded in continuous operation. The housing temperature limits the nominal speed, which must not exceed 90 °C. The nominal input speed specified in the catalogue applies to an ambient temperature of 20 °C. As can be seen in the diagram below, the temperature limit is reached more quickly in the presence of an elevated outside temperature. In other words, the nominal input speed must be reduced if the ambient temperature is high. The values applicable to your gearhead are available from WITTENSTEIN alpha on request.

Synchronization error
The synchronization error is equal to the variations in speed measured between the input and output during one revolution of the output shaft. The error is caused by manufacturing tolerances and results in minute angular deviations and fluctuations in ratio.

 

T

Technical data
The technical data relating to our products can be found on the relevant product pages. Alternatively, you can send
your requests, suggestions and comments to info@wittenstein-us.com.

Tilting moment (M2K)
The tilting torque M2K is a result of the axial and lateral forces applied and their respective points of application in relation to the inner radial bearing on the output side.

Torque (M)
The torque is the actual driving force of a rotary motion. It is the product of lever arm and force. M = F · l

Torsional backlash (jt)
Torsional backlash is the maximum angle of torsion of the output shaft in relation to the input. Torsional backlash is measured with the input shaft locked. The output is then loaded with a defined test torque in order to overcome the internal gearhead friction. The main factor affecting torsional backlash is the face clearance between the gear teeth. The low torsional backlash of WITTENSTEIN alpha gearheads is due to their high manufacturing accuracy and the specific combination of gear wheels.

Torsional rigidity (Ct21)
Torsional rigidity [Nm/arcmin] Ct21 is defined as the quotient of applied torque and generated torsion angle.
Ct21 = T/
It consequently shows the torque required to turn the output shaft by one angular minute. The torsional rigidity can be determined from the hysteresis curve. Only the area between 50 % and 100 % of T2B is considered for because this area of the curve profile can be considered linear.