Compressor Assembly, Model 4211 Carbon Dioxide Transfer Unit

(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. Motor 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. Multibreaker 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. 3-6