Zapi SEM1 - Protection Features

Page 6 SEM1
The two graphs show the output voltage from an uncalibrated potentiometer with respect
to the mechanical "zero" of the knob of one handle (MI and MA indicate the point at which
the speed microswitches close, 0 is the mechanical zero of the handle rotation).
The first graph shows the correspondence of the motor voltage without having made
the acquisition, while the second graph shows the same correspondence after signal
acquisition by the potentiometer.
The acquisition procedure is invalidated by the machine if the signals do not reach at
least 3V. It is possible to use a normal 3-wire pot., instead of one with central zero, set
on the mean value of its full stroke.
2.3 PROTECTION FEATURES
- Connection errors:
all the inputs are protected against connection errors.
- Thermal protection:
if the temperature exceeds 75°C, the maximum current is reduced in proportion to
the thermal increase. The temperature never exceeds 85°C.
- Low battery charge:
when the battery charge is low, the maximum current is reduced proportionally to the
battery discharge.
- Protection against accidental startup:
a precise sequence of operations is necessary for starting the machine; if these
operations are not carried out correctly, the machine will not start; the request for
running must be activated after the key.
- Protection against uncontrolled movements:
the contactor will not close if:
- the power unit is not functioning;
- the logic is not perfectly operating;
- Main contactor:
is to be installed in order to protect against reverse battery polarity;
- The chopper is protected against dust and liquid (IP41).