Toro 00062SL Rev I Greensmaster 3250 D Service Manual

Raise and Lower Cutting Units (Serial Number Above 270000000)
The gear pump (P2) is directly coupled to the hydrostat
through gear pump (P1). It supplies hydraulic pressure
for raising and lowering the cutting units, for the steering
circuit and for maintaining 100 to 150 PSI (6.9  to 10.0
bar)  to the  low  pressure  side of  the  traction  circuit
(charge pressure). Thegear pump(P2) takes itssuction
from the hydraulic reservoir. Maximum circuit pressure
is limited  by relief  valve (R5)  which is located  in the
steering control valve.
Lower Cutting Units
Circuit operation for lowering the lift cylinders is similar
to raising them.  However, the solenoid valve  (S3) re-
mains de--energized and  solenoid valve (S4) is  ener-
gized. Flow  is reversed to  and from the lift  cylinders,
lowering the cutting units.
When the cutting units are to be lowered, solenoid valve
(S2) is energized and blocks flow directly to the hydros-
tat. Flow  is  directed to  de--energized solenoid  valve
(S3), which directs  flow to the lift  cylinders. Hydraulic
pressure against the cylinder pistons moves their shafts
causing the cutting units to lower. At the same time, the
pistons push the hydraulic fluid out of the lift cylinders to
energized  solenoid valve  (S4). Flow  continues  back
through solenoid  valves (S3) to  the hydrostat.  Lower
speed for the front cutting units is controlled by the .055
orifice. A .055 orifice and adjustable flow control valve
forthecentercuttingunitallowsaslightdelayinlowering
that cutting unit.
During cutting unit hold (not raising or lowering) condi-
tions,  flow  from  the  gear pump  (P2)  is  by--passed
throughthesteeringcontrolvalveandde--energizedso-
lenoidvalve(S2)directlytothehydrostatandthecharge
relief valve (R4). Flow then returns to the hydraulic res-
ervoir.
Raise Cutting Units
When the cutting units are to be raised, solenoid valve
(S2) is energized and blocks flow directly to the hydros-
tat. Flow is directed  to energized solenoid valve (S3),
which directs flow to de--energized solenoid valve (S4)
and the lift cylinders. Hydraulic pressure against the cyl-
inder pistons  moves  their shafts  causing the  cutting
units to raise. At the same time, the pistons push the hy-
draulic fluid out of the lift cylinders and back through en-
ergized  solenoid valve  (S3)  to  the hydrostat.  Raise
speed for the front cutting units is controlled by a .055
orifice. A .055 orifice in the return line for the center cut-
ting unit allows a slight delay in raising that cutting unit.
To control pressure while lowering the cutting units, the
system is equipped with adjustable relief valve (R2) in
the hydraulic manifold.
When  solenoid  valves  (S2)  and  (S4)  de--energize,
spring action returns the valves to their original position
and by--passes flow back to the hydrostat stopping  lift
cylinder movement.
When  solenoid  valves  (S2)  and  (S3)  de--energize,
spring action returns the valves to their original position
and by--passes flow back to the hydrostat stopping  lift
cylinder movement. The lift cylinder position is locked in
place since there is no  complete circuit of flow to and
from the lift cylinders.
Greensmaster 3250--D
Page 4 -- 19
Hydraulic System (Rev. I)
Product Specification
CategoriesLawn Mower Manual, Sprinkler and Irrigation Manuals, Toro Sprinkler and Irrigation Manuals
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- 308 pages
Document TypeService Manual
LanguageEnglish
Product BrandToro. Customer Service Representatives are available by phone: Monday - Friday 7:30 a.m. to 9:00 p.m. (CDT) - Saturday 8:00 a.m. to 8:00 p.m. (CDT) - Sunday 10:00 a.m. to 8:00 p.m. (CDT)
Canada 1-888-225-4886 USA 1-888-384-9939, Lawn Mower
Document File TypePDF
Publishertoro.com
Wikipedia's PageToro Company
CopyrightAttribution Non-commercial
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