9
GB
4. Operation
4.1 Overcurrent release
The overcurrent release integrated into the motor swit-
ches off the motor if overloaded. The on/off switch must
be actuated again in order to restart the motor after
allowing it to cool
(see Fig. 3 + 4)
.
4.2 Power failure and low voltage release
(only MA II)
The on/off switch remains in position „I“ follo-
wing a break in the power supply (disconnection
of the mains plug, power failure). The switch
must be set to „0“ in such cases in order to
avoid uncontrolled restarting of the motor.
Motors of type MA II are optionally equipped with a low
voltage release. Versions with low voltage release do
not start automatically again after interruption of power
supply (pull plug and plug-in again). The on/off switch
must be actuated again in order to restart the motor.
If the supply voltage drops considerably below the rated
value (mains supply with major voltage fluctuations), the
low voltage release may make it impossible to switch
on the motor.
Motors of type MI 4 are not equipped with a low voltage
release.
4.3 Electronic speed controller
(only MI 4-230 E, MI 4-120 E, MI 4-100 E)
The motors of type MI 4 are also available with an elec-
tronic speed controller with which the flow rate can be
reduced as required. The knob for the electronic speed
controller is located near the on/off switch. The direction
for higher and lower speed is indicated by the scale. The
flow rate at minimum speed depends on the respective
mains supply. At a free discharge it corresponds to ap-
prox. 40% of the maximum flow rate, but is less in all
other cases
(see Fig. 5)
.
Do not stop the motor by using the speed con-
troller when operating at 60 Hz frequency.
Uncontrolled restart possible.
5. Maintenance
5.1 Carbon brushes
Single-phase series-wound motors have a commutator
with two carbon brushes. Carbon brushes are subject
to wear. They must consequently be inspected by an
authorized repair shop or the manufacturer after approx.
500 hours of operation in order to prevent destruction
of the motor due to complete abrasion of the carbon
brushes.
5.2 Changing the power cable
If the power cable is damaged or worn, it can be replaced
by a
qualified electrician
(see Fig. 6 + 7)
.
The mains plug must always be disconnected
before repairing the motor in any way.
MA II:
The cable used must at least be of type H05 RN-F.
MI 4:
The cable used must at least be of type H05 RN-F. The
on/off switch must be set to „I“ when replacing the motor
cover, otherwise the overcurrent release will jump out of
position or be damaged.
6. Repairs
Repairs should only be made by the manufacturer or
authorized Lutz-dealers. Only use genuine Lutz spare
parts.
