- 15 -
4.4 Operation in cold climates
In winter-season, when operating the pump in cold environment , it will be difficult to start up
the pump. It is called over-load operation because of high viscosity of the pump oil at low
temperature.
If the pump does not restart, warm up the pump oil, or try to keep the pump within the operating
temperature for a little while and then turn on the power again.
When the pump stops after rotating for a few seconds, open leak valve (B) and continuous
operation may become possible. After the pump has warmed up, close leak valve (B) and return
to ordinary op
e
ration (see Fig.5).
4.5 Backflow preventer
A backflow preventer is incorporated into the pump to prevent the oil from flowing back while
the pump is stopped.
The backflow preventer actuates in the case of an emergency including power failure. So, after
the pump is stopped due to a power failure, follow the procedures mentioned in “
4.3 Stopping
the operation
” to stop the operation.
① To stop the pump, always close vacuum valve (A) and then open leak valve
(B). If this procedure is neglected, the pump oil fills the cylinder,
making restart difficult or causing damage to the pump. The pump oil also
may flow back to the vacuum chamber side
(see Fig.5)
.
② If vacuum valve (A) is not closed, air may leak into the device side through
the pump increasing the pressure
(see Fig.5)
.
4.6 Thermal protector
A manually reset thermal protector is incorporated in the motor in order to interrupt the power
circuit of the motor and prevent damage to the motor when an over current flows through the
motor due to a stop in rotation or overload resulting from the pump malfunctioning during
operation. The type of thermal protector to be used depends on the pump model.
Table 3 Characteristics of the thermal protector
Model
Operating
characteristic
Non-operating
characteristic
GCD-051X
1
φ
,200W
25.0(A) at 25
℃
7.0(A) at 60
℃
1
φ
,400W
28.0(A) at 25
℃
7.8(A) at 60
℃
GCD-136X
3
φ
,400W
3.6(A) at 60
℃
2.3(A) at 60
℃
1
φ
,550W
35.0(A) at 25
℃
10.0(A) at 60
℃
GCD-201X
3
φ
,700W
17.0(A) at 25
℃
4.0(A) at 60
℃
When the thermal protector has been actuated, turn off the switch and contact us.
The motor is very hot when the thermal protector has actuated. Never touch it with your hand.
When the cause of the malfunction has been eliminated, check that the motor has cooled down,
and then press the manual reset button to restart operation (see “
6.5 Trouble check list
”).
Warning
