(4), motor (7), multibreaker (l), power cable (9),
and base (8). The only difference between the
models lies in the type of compressor supplied;
however, the compressors are interchangeable
between the models. A spare parts kit, recharging
transfer fittings, and charging fittings are used in
conjunction with the units.
The repulsion start induction single-phase
motor, shown in figure 3-3, is a 115- to 230-volt,
60-cycle, three-fourths horsepower unit. It
operates at 1750 rpm and draws 9.8 amperes at
115 volts. This type of motor supplies very high
starting torque with a very low starting current.
In starting, the motor has repulsion motor
characteristics; but at running speeds, it functions
as an induction motor since the motor windings
are automatically short-circuited and the brushes
a r e l i f t e d f r o m t h e c o m m u t a t o r w h e n t he
operating speed is approached.
The thermal, magnetic multibreaker, shown
in figure 3-3, is a two-pole, 115-volt ac, 20-ampere
unit installed to protect the power circuit from
overloads. In addition, it acts as a manual
ON/OFF switch for the operation of the transfer
unit. If the multibreaker trips because of a power
overload, you may reset it by placing the switch
first to OFF and then to ON.
Compressor Assembly, Model 4211
Carbon Dioxide Transfer Unit
This unit, shown in figure 3-4, is a two-stage,
single-action, displacement-type compressor. The
running gear assembly actuates the unit and
transfers the liquid carbon dioxide from the
supply cylinder to the cylinder being recharged.
The lower section consists of a cylinder body (6),
plunger (7), molded metallic packing (8), spacer
(10), and plunger guide (9). The plunger (7), which
acts as a piston and transfers the liquid carbon
dioxide, is connected to the crosshead of the
running gear assembly. The upper section of the
unit consists of a cylinder head (2) with an intake
and outlet port, an intake valve (11), a discharge
valve disc (4), and a discharge valve cap (l). A
safety disc and washer, located in the cylinder
head behind the safety disc plug (13), releases the
carbon dioxide from the compressor when the
pressure exceeds the 2650- to 3000-psi range.
Figure 3-4.Compressor Assembly, Model 4211 Carbon
Dioxide Transfer Unit.