Motion Actuator - Manual (Page 22)

TERM DESCRIPTION OF TERM
Electrical time
constant
Electrical time constant is the time taken for a step current input to the motor to reach 63.2% of its
value.
Continuous
working voltage
Continuous working voltage is the maximum allowable continuous voltage between any two motor
phases or between any motor phase and the motor safety earth.
Pole pitch Pole pitch is the distance in millimetres for one complete electrical cycle (between like magnetic
poles).
Power dissipation Power dissipation is the maximum power that can be dissipated by the motor when the motor
phases are at their maximum operating temperature, the ambient temperature is 25°C, the motor
is not moving and there is no forced cooling. It is quoted with and without the addition of a 25 x 25
x 2.5cm heatsink plate mounted with thermal grease to the mounting surface of the motor.
Maximum phase
temperature
Maximum phase temperature is the maximum operating temperature for the motor phases. It is
limited to provide a safe operating temperature for the magnets.
R
thphase-houslng
R
thphase-houslng
is the temperature rise from the motor housing to the motor phases for an input
power of 1 watt to the motor. The motor is not moving, there is no forced cooling and no additional
heatsinking.
R
thhousing-ambient
R
thhousing-ambient
is the temperature rise from ambient temperature to the motor housing for an input
power of 1 watt to the motor. The motor is not moving and there is no forced cooling. It is quoted
with and without the addition of a 25 x 25 x 2.5cm heatsink plate mounted with thermal grease to
the mounting surface of the motor.
Thermal time
constant
Thermal time constant is the time taken for the motor phases to cool to 36.8% of the difference
between motor phase and ambient temperatures when there is no current flowing, the motor is not
moving there is no forced cooling and no additional heatsinking.
ABBREVIATIONS
The abbreviations used in this Guide are listed in the following table.
A
pk
Ampere peak PCB Printed circuit board
A
rms
Ampere root mean square PUR Polyurethane
AWG American Wire Gauge PVC Poly Vinyl Chloride
COS cosine s second
d.c. direct current SIN sine
EMC Electro-Magnetic Compatibility TYP Typical
EMF Electro-Motive Force UL Underwriters Laboratory
kg kilogramme V Volt
m metre V
pk
Volt peak
mA milliampere V
pk-pk
Volt peak to peak
mH millihenry V
rms
Volt root mean square
mm millimetre W Watt
MTG Mounting °C degrees Celsius
N Newton mm micrometre (micron)
PTC Positive Temperature Coefficient
Page 16
Appendices ServoTube 38 Installation Guide