Gear speed change, Motor circuit breaker, Speed display – IKA RW 28 digital User Manual

Page 8: Output shaft

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8

(Fig 3)

After the locking knob (D, see Fig. 1) on the left

side of unit is pulled, the gears could be taken out of
mesh by turning in counterclockwise direction to the
bearing bushing on the black knurled surface (E, see
Fig. 1) above the chuck. The centre axis of the stir-

ring apparatus is thus shifted in a radial direction.
The bearing bushing is then axially positioned up or
down in accordance with the range which is to be
set. The gears are put back into mesh by turning the
bearing bushing back (clockwise) and the centre axis
of the agitator is swiveled into the original position
until the locking knob (D, see Fig. 1) catches.

Gear speed change

The ball race capacitor motor (degree of protec-
tion IP 42) is maintenance free. In its winding it
carries a special overheating circuit breaker (self-
locking temperature limiter) which shuts down
the motor permanently if the permissible motor
temperature is exceeded.
This special type of circuit breaker is used when
the automatic reactivation of the protected unit
after overheating is undesirable or impermissible.
The principle of the temperature limiter is that of a
switch that heats up and isolates the motor from
the power supply when the maximum permissible
temperature is reached.

Motor circuit breaker

The rotation speed is adjusted by means of the
rotary knob (B, see Fig. 1) on the side of the

overhead stirrer.

Speed display

When the self-locking temperature is exceeded,
Er 4 is shown on the display (see section “Error

codes“).

In this case the unit can only be switched back on
after it has been switched off for approx. 4-5 min-
utes by pressing the rocker switch (A, see Fig. 1)

on the front or by disconnecting the mains plug.
After this short cooling, the contacts in the current
circuit are closed again and the unit is operational
once more.

It should be necessary to change the gear speed
in the course of setting up an experiment or pro-
cess with glass apparatus, then attention must be
paid to the movement of the stirrer element by
the eccentric bearing bush and to the movement
in the axial direction. If this is unacceptable, the
stirrer element must be loosened in the chuck.

Only change the gear posi-

tion at standstill!

Output shaft

The clamping chuck and output shaft permit clamp-
ing IKA

®

recommend stirrer tools (see “Permitted

IKA

®

Stirrer tools“ section).

The output shaft is designed as a hollow shaft,
and the opening on the top side of the housing is
closed with a stirrer cover. When the stirrer cover is
opened, it is possible for stirring shaft to be pushed
out over the top edge of the housing at standstill,

e.g. during changing container.

For safety reason, the stirrer cover must be pushed
back into the opening of the housing so that it is
properly closed. This is the only way to ensure that
working with the unit is safe and that media cannot
enter the instrument.

Please see section “Safety

instructions“!

The rotational speed is displayed directly in revolu-
tions per minute (rpm) on the display (C, see Fig. 1).

DANGER

DANGER

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