Parker GVM Series User Manual

- 37 –
18-06-08 PVD3668_GB_GVM_June_2018
3.2.2. Time constants of the motor
3.2.2.1. Electric time constant:
phph
phph
elec
R
L
_
_
 
With following values given in the motor data sheet
L
ph_ph
inductance of the motor phase to phase [H],
R
ph_ph
resistance of the motor phase to phase at 25°C [Ohm].
Example:
Motor series GVM210-400-DPW
L
ph_ph
= 0.316 mH or 3.16E-4 H
R
ph_ph
at 25°C = 0.15 Ohm
 
elec
= 3.16E-4/0.015 = 21 ms
An overall summary of motor time constants is given later.
3.2.2.2. Mechanical time constant:
3
*)
3
*3(
**5.0
*
*
__
_
_
_
phphphph
phph
nph
nph
mech
KeKe
JR
KeKt
JR
 
2
_
_
)(
**5.0
phph
phph
mech
Ke
JR
 
With following values obtained from the motor data sheet:
R
ph_ph
resistance of the motor phase to phase at 25°C [Ohm],
J inertia of the rotor [kgm²],
Ke
ph_ph
back emf phase coefficient phase to phase [V
rms
/
rad/s
].
The coefficient Ke
ph_ph
in the formula above is given in [V
rms
/rad/s]
To calculate this coefficient from the datasheet, use the following relation:
60
1000**2
]1000/[
_
]//[
_

rpmV
phph
sr adV
phph
rms
rms
Ke
Ke 
Example:
Motor series GVM210-400-DPW
R
ph_ph
at 25°C = 0.015 Ohm
J = 0.07 kgm²
Ke
ph_ph
[V
rms
/
1000rpm
] = 76.9 [V
rms
/
1000rpm
]
 Ke
ph_ph
[V
rms/rad/s
] = 76.9/(2**1000/60) = 0.734 [V
rms/rad/s
]
 
mech
=0.5*0.015*0.07/(0.734²) = 0.97 ms
Remarks:

Parker GVM Series Specifications

General

Brand	Parker
Model	GVM Series
Category	Engine
Language	English