Filter
Top Products
6564
A real concept:
High-frequency Tools
How a good idea was consistently
further developed: The designation
’high-frequency tools’ came to be
known through the market launch
of the tools and was given to those
powerful high-frequency tools with
asynchronous motors, operated
with three-phase current at an
increased frequency of 200 or 300
Hz. In a physical sense, there is no
real connection between these
tools and genuine high-frequency
technology, but they still came to
be known under this name.
The operating
frequency determines
the performance
In hand tools, rotary current at
increased frequency of 200 or
300 Hz combines high electrical
performance with minimal motor
weight. As the frequency of the
rotary current increases, there is
a proportional increase in motor
speed and thus in the perfor-
mance of asynchronic motors.
This is limited by the maximum
admissible circumference velocity
(operating rotational speed) of
the tools. An optimum perfor-
mance/weight ratio is achieved
by high-frequency tools operating
at a frequency of 200 to 300 Hz
(Fig. 1). Large differences bet-
ween motor rotational speed and
operating rotational speed
require larger gears. This means
that weight savings from the
rotary current drive are negated
by the increased weight from the
stepdown gearing.
High-frequency installations using
exclusively grinders should be
operated at 300 Hz. Using rotary
current at increased frequency
optimally fulfils the demand for
light yet high-performance hand
tools.
Fig. 1 The graph shows the dependence of motor and gearing weight on frequency at constant motor performance and rated rotational speed.
300 Hz yields an optimum performance/weight ratio.
Weight (kg)
Total weight
Gear weight
Motor weight
Frequency (Hz)
0 100 200 300 400 500
ROBUST TECHNOLOGY FOR LONG-TERM
HEAVY-DUTY USE.
A high-frequency motor is a three-phase current motor with a short-circuit rotor. Its stator and
rotor consist of a laminated sheet-metal bundle. If the stator winding of the motor is connected
to the three-phase current supply, a magnetic field is created (rotary field), which runs through
the motor due the arrangement of the winding and which is dependent on number of pole pairs
and the frequency.
Rotor
Stator
Fan
Housing