Parker TM Series, Technical Manual, Page: 51 / 129

51 - PVD 3622_GB_TM_January 2014.Docx
Remarks:
For a DC motor, the mechanical time constant

mech
represents the duration needed
to reach 63% of the final speed when applying a voltage step without any resistant
torque, if the electrical time constant is much smaller than the mechanical time
constant.
An overall summary of motor time constants is given a little further.
3.2.10.3. Thermal time constant of the copper:
copper iron copper therm
Cth Rth *
_


] / [
] [ ] / [
389 *
K kg J
Kg
copper
K J
copper
Mass Cth



With:
Rth
copper_iron
thermal resistance between copper and iron [°K/W]
Cth
copper
thermal capacity of the copper [J/°K]
Mass
copper
mass of the copper (winding) [kg]
Hereunder is given an overall summary of motor time constants:
Type
Electric time
constant [ms]
Mechanical time
constant [ms]
Thermal time
constant of copper
[s]
TMW204L 11 2,1 41
TMW205L 12 1,6 38
TMW206L 12 1,4 36
TMW207L 13 1,4 36
TMW208L 13 1,2 35
TMW304L 11 2,3 43
TMW305L 12 2,2 40
TMW306L 12 1,8 38
TMW308L 13 1,8 36
TMW30AL 14 1,5 35
TMW404L 15 3,0 43
TMW405L 16 2,4 40
TMW406L 17 1,9 38
TMW408L 18 1,6 36
TMW40AL 18 1,6 34
TMW40CL 19 1,3 34