GB1129946A - Control system for refrigerating apparatus - Google Patents

Abstract

1,129,946. Time switches. RANCO Inc. 2 June, 1967 [15 June, 1966], No. 25695/67. Heading H1N. To ensure that a refrigerator compressor motor cannot be re-energized until a predetermined time interval has elapsed following deenergization a control device comprises a change-over contact normally latched in engagement with a first "fixed" contact in series with the motor circuit and tripped open when the motor circuit is opened, being subsequently closed by a cam driven through gearing by a synchronous timer motor which is energized via a second "fixed" contact engaged by the changeover contact when in its unlatched condition. In a first embodiment (Fig. 2) a solenoid 56 is connected in parallel with the compressor motor (15, Fig. 1, not shown) so that armature 55 is lifted against spring 62. When the motor (15) is de-energized the armature 55 is released and its kinetic energy causes projection 60 to impinge on pivoted latch 48 (as in Fig. 3, not shown), opening contacts 35, 36 in the compressor motor circuit and closing contacts 35, 37 in the timer motor circuit. Cam 31 is then driven by the timer motor (30, Fig. 1, not shown) until rise 33 lifts contact 37 and hence contact 35, allowing latch 48 to restore (Fig. 4, not shown). An insulating spacer 42 keeps contacts 35, 36 open until contact 37 drops off rise 33 whereupon the condition shown in Fig. 2 is re-established. A revolution of cam 31 may take five minutes, for example. In a second embodiment (Fig. 6) a solenoid 140 is connected across certain protective switches (103, 104, Fig. 5, not shown) in series with a compressor motor (100) such that it is energized when either of these switches opens. This causes armature 137 to impinge on adjustment screw 136 of pivoted lever 132 and displace the end 125 of resilient blade 121 carrying changeover contact 120, which is inherently biased towards fixed contact 114 in the timer motor circuit but latched as shown by a relatively stiff member 126 overlying projection 124. Displacement of end 125 allows contact 120 to disengage contact 115 in the circuit of the compressor motor and solenoid 140 and energize the timer motor (111) via contact 114. Cam 110 is thus driven until rise 112 lifts member 126 over projection 124 (Fig. 8, not shown), and the drop 113 then restores the contacts to the position shown.