OP-755 Part 2 Pages 197-401 - Personal Page of GENE SLOVER

269
Starting circuit electrical interlock
Control lever dashpot
Safety latch release valve
Oil filters
Motor-starting interlock
35. The installed arrangement of each such power plant
(but not those elements located in the hoist trunk and at the
operator! s station) is as shown on drawings number 216453,
216454, for the right and center hoists, and drawings number
230757 and 230758, for the left hoist. In these assemblies
the electric motor is mounted with its rotor shaft vertical
and direct coupled to the A-end pump. The auxiliary pump is
driven through a reduction gear by the motor. Both pumps are
supplied from the same tank. Leads connect the main pump with
the hydraulic motor' (B-end) and elements of the A-end valve
block. The auxiliary pump is arranged in a system of leads
so that it replenishes theA-end supply, provides control circuit
pressure to the brake operating cylinder, the safety Latch,
release valve and operating cylinder, the latch and vent valve,and
elements of the A-end valve block. The control lever dashpot
is a closed hydraulic element that is independent (hydraulically)
of the main and control circuits.
36. The purpose of the preceding indicated arrangement
is to provide hydrau-lic power for hoisting and lowering the
car and for controlling those movements in conjunction with
an interlocking system for the trunk doors. The arrangements
include devices to limit the ra tesof acceleration and de-celeration
of the car and other provision to prevent falling of
the car in event of power failure or of rupture of pipe lines.
These and other features of the drive are provided by the following
design arrangements.
(a) The electric hydraulic drive is designed to be
normally controlled by a "Servo" system. This
system controls the offset of the A-end pump
with pressure operated piston. Pressure is
derived from a control and superCharging pump
loca ted in the top of the A-end. This auxiliary
f'unct Lons for two methods of ftServo!! operation,
designated SERVOELECTRICALand SERVOMECHAN-
ICAL. Normal operation of the drive is through
ftServo Electrical!! control.
(b) Servo electrical control is a system utilizing
car limit switches, door actuated switches and
a starting lever switch to open and close a
circui t which shifts an operating valve of the
hydraUlic system to initiate servo piston
stroke. Car acceleration, high speed and de-