Danfoss Series 51-1 Controls B1, Series 51-1 Controls B2, Series 51-1 Controls B7, Series 51-1 Controls E1, Series 51-1 Controls E2 Service guide

MAKING MODERN LIVING POSSIBLE

Service Manual

Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

powersolutions.danfoss.com

Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

Revision history	Table of revisions
	Date	Changed	Rev
	February 2015	Danfoss layout	BA
	January 2008	First edition	AA

2	11009443 • Rev BA • February 2015

Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8
Contents
Introduction
	Safety precautions............................................................................................................................................................................	4
	Unintended machine movement..........................................................................................................................................	4
	Flammable cleaning solvents.................................................................................................................................................	4
	Fluid under pressure..................................................................................................................................................................	4
	Personal safety.............................................................................................................................................................................	4
	Hazardous material....................................................................................................................................................................	4
	Symbols used in Danfoss literature............................................................................................................................................	5
	General instructions........................................................................................................................................................................	5
	Keep it clean..................................................................................................................................................................................	5
	Inspect for system contamination........................................................................................................................................	6
	Replace the O-rings and gaskets...........................................................................................................................................	6
	Lubricate all moving parts.......................................................................................................................................................	6
	Torque procedure.......................................................................................................................................................................	6
	Overview..............................................................................................................................................................................................	6
Required tools, gauge port and orifice locations
	Required tools....................................................................................................................................................................................	8
	Port locations and gauge installation.......................................................................................................................................	8
	Orifice locations................................................................................................................................................................................	9
N1 two-position control
	Functional Description.................................................................................................................................................................	10
	Adjustments.....................................................................................................................................................................................	10
	Minor repair......................................................................................................................................................................................	10
E1, E2, E7, F1, F2 two-position controls
	Functional description.................................................................................................................................................................	13
	Adjustments.....................................................................................................................................................................................	14
	Minor repair......................................................................................................................................................................................	14
B1, B2, B7 two-position controls
	Functional description.................................................................................................................................................................	17
	Adjustments.....................................................................................................................................................................................	17
	Minor repair......................................................................................................................................................................................	17
T1, T2, T7, TA, TH Pressure Compensator (PC) controls
	Functional Description.................................................................................................................................................................	20
	Overview......................................................................................................................................................................................	20
	Option TA....................................................................................................................................................................................	20
	Option TH....................................................................................................................................................................................	20
	Option T1T2/T7 .........................................................................................................................................................................	21
	Brake pressure defeat..............................................................................................................................................................	21
	Schematics..................................................................................................................................................................................	23
	Adjustment.......................................................................................................................................................................................	24
	PC start pressure.......................................................................................................................................................................	24
	Minor repair......................................................................................................................................................................................	26
	Control housing........................................................................................................................................................................	26
	TA option components...........................................................................................................................................................	27
	TH option components..........................................................................................................................................................	28
	T1, T2, T7 option components.............................................................................................................................................	29
	Servo/PC supply option CA (with hydraulic signal).....................................................................................................	30
	Servo/PC supply option C2 (without external signal).................................................................................................	31
	Servo/PC supply options D1/D2/D7..................................................................................................................................	32
	Servo/PC supply options L5/R5...........................................................................................................................................	34

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Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

Introduction

Safety precautions

Always consider safety precautions before beginning a service procedure. Protect yourself and others from injury. Take the following general precautions whenever servicing a hydraulic system.

Unintended machine movement

W Warning

Unintended movement of the machine or mechanism may cause injury to the technician or bystanders. To protect against unintended movement, secure the machine or disable/disconnect the mechanism while servicing.

Flammable cleaning solvents

W Warning

Some cleaning solvents are flammable. To avoid possible fire, do not use cleaning solvents in an area where a source of ignition may be present.

Fluid under pressure

W Warning

Escaping hydraulic fluid under pressure can have sufficient force to penetrate your skin causing serious injury and/or infection. This fluid may also be hot enough to cause burns. Use caution when dealing with hydraulic fluid under pressure. Relieve pressure in the system before removing hoses, fittings, gauges, or components. Never use your hand or any other body part to check for leaks in a pressurized line. Seek medical attention immediately if you are cut by hydraulic fluid.

Personal safety

W Warning

Protect yourself from injury. Use proper safety equipment, including safety glasses, at all times.

Hazardous material

W Warning

Hydraulic fluid contains hazardous material. Avoid prolonged contact with hydraulic fluid. Always dispose of used hydraulic fluid acm³ording to state, and federal environmental regulations.

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Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

Introduction

Symbols used in Danfoss literature

WARNING may result in injury

CAUTION may result in damage to product or property

Reusable part

Non-reusable part, use a new part

Non-removable item

Option - either part may exist

Superseded - parts are not interchangeable Measurement required

Flatness specification

Parallelism specification

External hex head

Internal hex head

Torx head

O-ring boss port

Tip, helpful suggestion

Lubricate with hydraulic fluid

Apply grease / petroleum jelly

Apply locking compound

Inspect for wear or damage

Clean area or part

Be careful not to scratch or damage Note correct orientation

Mark orientation for reinstallation Torque specification

Press in - press fit

Pull out with tool – press fit

Cover splines with installation sleeve

Pressure measurement/gauge location or specification

The symbols above appear in the illustrations and text of this manual. They are intended to communicate helpful information at the point where it is most useful to the reader. In most instances, the appearance of the symbol itself denotes its meaning. The legend above defines each symbol and explains its purpose.

General instructions

Keep it clean

You can complete many repairs or adjustments without removing the unit from the machine, if the unit is accessible and you can thoroughly clean it before beginning any procedures.

Cleanliness is a primary means of assuring satisfactory motor life on either new or repaired units. Clean the outside of the motor thoroughly before disassembly. Take care to avoid contamination of the system ports. Cleaning parts with a clean solvent wash and air drying is usually adequate.

As with any precision equipment, keep all parts free of foreign materials and chemicals. Protect all exposed sealing surfaces and open cavities from damage and foreign material. Cap all hoses after removal, and plug all open ports. Cover any unattended parts with a protective layer of plastic.

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Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

Introduction

Inspect for system contamination

Inspect the motor for signs of system contamination. If you find contamination, fully disassemble, clean and inspect all components of the motor.

Replace the O-rings and gaskets

Replace all O-rings and gaskets. Discard them only after you make certain that you have the correct replacement parts. Lightly lubricate all O-rings with clean petroleum jelly before assembly.

Lubricate all moving parts

During reassembly, coat all moving parts with a film of clean hydraulic oil. This helps lubricate the surfaces during start-up.

For fluid quality requirements, refer to 520L0463 Hydraulic Fluids and Lubricants, Technical

Information.

Torque procedure

During reassembly, cross torque all retaining screws to the given value. Do not overtorque.

Overview

Series 51-1 motor controls operate by routing the flow of oil to the servo piston in the motor’s endcap. The servo piston has a differential area of 2:1.

•The larger area acts to reduce displacement.

•The smaller area works to increase displacement.

Due to the simplified design of the Series 51-1, only two-position and pressure compensator controls are available.

An external hydraulic or electric signal operates two-position controls. Pressure comes from the low side of the system loop and the control routes it to either the rod or piston end of the servo piston to set the motor’s displacement.

Pressure compensator (PC) controls automatically set the displacement of the motor based on system pressure. PC controls allow the motor to increase available torque based on system demand by increasing the motor’s displacement.

The motor defaults to minimum displacement until system pressure reaches the PC set pressure. The PC set pressure is adjustable in a range from 110 to 370 bar [1595 to 5365 psi]. Pressure is taken from the high side of the system loop to operate the servo piston.

PC controls:

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Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

Introduction

•can have a maximum displacement lock that holds the displacement at maximum when a hydraulic or electric signal is applied.

•can be equipped with a brake pressure defeat option that holds the motor at minimum displacement during dynamic braking. A hydraulic or electric signal operates the brake pressure defeat feature.

Differential area servo piston

Value segment

Servo piston

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Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

Required tools, gauge port and orifice locations

Required tools

You can perform the service procedures in this manual using common mechanic’s hand tools. Special tools, if required, are shown. Calibrate pressure gauges frequently to ensure accuracy. Use snubbers to protect pressure gauges. For controls N*, E*, F*, and B* use a 600 psi [45 bar] gauge for M3, M4, and M5 gauge (pressure) ports. For T* controls use a 10,000 psi [600 bar] gauge for M3 and M4 gauge (pressure) ports..

Port locations and gauge installation

Two-position controls

	M3 Gauge port	M3 Gauge port
	Servo pressure min-angle	Servo pressure min-angle
M3 Gauge port	0.5625 [9/16] 18UNF-2B	0.5625 [9/16] 18UNF-2B
Servo pressure min-angle
0.5625 [9/16] 18UNF-2B
	M5 Gauge port	M5 Gauge port
	Servo supply pressure	Servo supply pressure
M5 Gauge port	0.5625 [9/16] 18UNF-2B	0.5625 [9/16] 18UNF-2B
Servo supply pressure
0.5625 [9/16] 18UNF-2B
MON*	MOE*
	MOF*	MOB*

	M4 Gauge port	M4 Gauge port
	Servo pressure max-angle
		Servo pressure max-angle
	0.5625 [9/16] 18UNF-2B
		0.5625 [9/16] 18UNF-2B

P101 242E N1 Control

Pressure Compensator

adjusting screw

M3 Gauge port

Servo pressure min-angle

0.5625 [9/16] 18UNF-2B

M4 Gauge port

Servo pressure max-angle

0.5625 [9/16] 18UNF-2B

T* Controls

P101 244Ea

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Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

Required tools, gauge port and orifice locations

Orifice locations

T3

	U5
	U5
U5	U5

B* control codes

	T2
	T3
	U5
	U5
T3	T2

N* control codes

U5

T2

T3

T3

T2

E* and F* control codes

T3

T3

E100 293E

T* control codes

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Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

N1 two-position control

Functional Description

The N1 control consists of a ported housing that is mounted on the endcap over the piston end of the servo piston.

The housing contains two external ports, designated M3 and M5. These ports serve as the control inputs. There are three interface ports1 that connect to the rod and piston ends of the servo, and to the servo supply port in the endcap. The servo supply connects to the output of the loop flushing spool so it dispenses low loop pressure to the control regardless of motor direction.

The control routes servo supply pressure through orifices U5 and T2 to the rod end of the servo piston. This holds the motor at maximum displacement until pressure from an external source is applied at port M3. This signal pressure then routes through orifice T3 to the piston end of the servo, shifting the motor to minimum displacement. Typically 20 to 25 bar [290 to 360 psi] is necessary to shift the motor.

You may also install a plug in place of orifice U5, blocking the connection to servo supply. You can then apply pressure from an external source at port M5 to shift the motor to maximum displacement.

Orifices T2 and T3 set the control response by limiting the flow to either end of the servo piston.

Schematic diagram
N1 control schematic diagram
	L2	N
	A
		n
		min.
		disp.
	T3
	T2
		L1
	U5
M5	B	M4
X1(M3)
		P001 779E

Adjustments

This control requires no adjustments.

Minor repair

Disassembly

1.Thoroughly clean all external surfaces before disassembly. Mark components as necessary to ensure you reassemble the unit correctly.

2.Remove the 4 screws (M16). Use an 8mm internal hex wrench.

3.Remove the control housing (M1N*) from the endcap.

1 Interface ports are those between the control and the endcap.

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Service Manual	Series 51-1 Controls B1, B2, B7, E1, E2, E7, F1, F2, N1, T1, T2, T7, TA, TH, P7, P8

N1 two-position control

4.After ensuring you have the correct replacement parts, remove and discard the interface O-rings (G42), or remove the control gasket (G420) from the endcap.

5.Using a 1/4-inch internal hex wrench remove plugs (M14) from the housing. Fasteners are metric. Porting plugs are SAE.

6.Using a 1/8-inch internal hex wrench remove plug (M12) from the housing.

7.After ensuring you have the correct replacement parts, remove and discard O-rings (M12A and M14A) from the plugs (M12 and M14).

8.If necessary, remove T2, T3, and U5 control orifices. Use a 3mm internal hex wrench. Tag the orifices for reassembly.

N1 control exploded
M14
	M16
	M12
	M1N*
G42	M14
G420

P101176

Inspection

Clean and inspect all parts for damage. Check orifices and passages in control housing for foreign material.

Assembly

1.If removed, install control orifices T2, T3, and U5 to their proper location. Using a 3mm internal hex wrench, torque the orifices to 6 N•m [4 lbf•ft].

2.Lubricate and install new O-rings on the housing plugs (M12). Using a 1/8-inch internal hex wrench, torque them to 9 N•m [7 lbf•ft]

3.Lubricate and install new O-rings on the housing plugs (M14). Using a 1/4-inch internal hex wrench, torque them to 37 N•m [28 lbf•ft].

4.Using clean petroleum jelly to retain them, install new interface O-rings (G42) or a new control gasket (G420) on the endcap.

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