______ HSD __________________________________________________________________________________
4.3.2 MOTOR THERMISTOR
In some versions cuold be inserted a PTC thermistor in the stator windings to monitor temperature. Electrical resistance
from the thermistor increases rapidly as it reaches trip temperature (normally 100°C or 130°C depending on the model).
The signal from the thermistor must be fed to a control device to stop the machine in order to protect the electro-spindle
from the effects of overheating.
Thermistor trip temperature depends on the model of electro-spindle. (See data sheet)
The thermistors used in these electro-spindles comply with DIN 44081-44082 standards.
Temperature – Resistance curve
according to DIN 44081/44082
Main specifications
Nominal trip temperature
TNF= from 50°C to 200°C
in steps of 10K or 5K
Characteristic values for
PTC thermistors
Resistance in
temperature range from
-20°C to TNF-20K
Resistance at TNF-5K
Resistance at TNF+5K
Resistance at TNF+15K
Resistance
20 to 250Ω
≤550Ω
≥1330Ω
≥4000Ω
Measurement
voltage
≤ 2.5 V−
≤ 2.5 V−
≤ 2.5 V−
≤ 7.5 V− pulse
Figure 4.1
IF THE SHAFT BLOCKS WHILE THE TOOL IS STILL BEING PUSHED AGAINST THE PIECE BEING WORKED, THE BEARINGS OF THE
SPINDLE COULD BREAK; IF YOU WAIT TOO LONG BEFORE REMOVING THE TOOL FROM THE PIECE AND STOPPING THE
ROTATION, THE STATOR COULD BE BURNT.
Y580100001 rev.03 ____________________________________________________________________ 11
