Gear Speed Change; Speed Display; Motor Circuit Breaker - IKA LABORTECHNIK RW 28 basic Instrucciones De Manejo

justed by the helical clutch according to the moment acting on the
stirrer shaft. A low torque results in a low down-pressure; a high
torque results in a high down-pressure.

Gear Speed Change

(Fig 2)
After the catch knob on the left side of unit is pulled, the gears are
taken out of mesh by turning in a direction counterclockwise to the
bearing bushing on the black knurled surface above the chuck. The
centre axis of the stirring apparatus is thus shifted in a radial direc-
tion. 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 swivelled into the original position until
the catch knob catches.
Should it be necessary to change the gear speed in the course of
setting up an experiment or process with glass apparatus, then
attention must be paid to the movement of the stirrer attachment by
the eccentric bearing bush and to the movement in the axial direction.
If this is unacceptable, the stirrer attachment must be loosened in the
chuck.

Motor Circuit Breaker

The ball race capacitor motor (degree of protection IP 42 only
together with the factory-provided switch box) 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
12
switch that heats up and isolates the motor from the power supply
when the maximum permissible temperature is reached.
When the self-locking temperature sensor is tripped, the yellow
glow lamp on the front plate of the unit lights up to indicate the
motor overload and the stoppage of the motor. In this case the unit
can only be switched back on after it has been switched off for
approx. 4-5 minutes by pressing the rocker switch on the front plate
or by disconnecting the mains plug.
After this short cooling period, the contacts in the current circuit are
closed again and the unit is operational once more.

Speed Display

The speed on the RW 28 basic agitator is adjusted by means of the
rotary button.
The speed that is set can be read on the label (Fig. 2) attached to
the side of the unit using the marking on the motor support. (The
values are only valid for low agitator shaft lows.)
Commissioning
For correct use, the stirrer machine must be fixed with a cross
sleeve (eg R261 or R270) to a stable stand (eg R2722 or R2723).
The stirrer container should always be fixed with a tensioner (eg
RH2) for safety reasons.
A minimum distance of 40 mm must be provided for between the
agitator housing elements and the stand leg in order to prevent the
motor from bumping against the stand at the lowest speed setting.
RW280597EU