T1, T2, T3, T4, Ta, Th, Tm, Tn; Operation; Ta Control; Th Control - Danfoss 51 Series Service Manual

Service Manual

T1, T2, T3, T4, TA, TH, TM, TN

Operation

N Module Option Codes

22
Series 51 Two Position Controls Service Manual

TA Control

The TA control does not have two-position operation, it is Pressure Compensating Over-Ride (PCOR)
operation only. It uses a sensing piston (M12) to shift the 4-way valve when system pressure reaches the
PCOR setting. The 4-way valve then ports high system pressure to the servo piston, shifting the motor
toward maximum displacement. The 4-way sleeve is reverse logic: the motor is biased to minimum
displacement. The sensing piston has different area lands that allow high system pressure between the
lands to push the 4-way valve against the threshold spring. The PCOR function threshold setting is
adjustable from 110 to 370 bar [1595 to 5365 psi].

TH Control

The TH control is a hydraulic two-position override with the PCOR function as described above. This
control holds the motor at maximum displacement when an external signal of 10 to 35 bar [145 to 507
psi] is applied to the X1 port.
The non-signal pressure at the X1 port must be equal to the motor's case pressure or else the PCOR
setting will be altered.

T1, T2, T3, T4 Control

The Tl, T2, T3, T4 controls are electric, two-position override with the PCOR function discussed earlier.
These controls hold the motor displacement at maximum when an external electric signal is applied. The
solenoid is available in four configurations: 12V (T1) or 24V (T2) with DIN 4360 connectors and 12V (T3) or
24V (T4) with Jet jr. Timer connector with Zener commutating diode.

TM, TN Controls

The TM and TN controls are electric two-position with a proportional PCOR solenoid. Full current to the
solenoid holds the motor at maximum displacement. Lesser current varies the PCOR setting, no current
equals full PCOR setting. This coil is available in two configurations; 12V (TM) or 24V (TN) with jet Jr. Timer
connector with Zener commutating diode. These controls also have an electric Brake Pressure Defeat
(BPD) spool. An electric solenoid shifts the BPD spool when energized. This coil is available in two
configurations; 12V (E7- F7) or 24V (E8 - F8) with Jet jr. Timer connector with Zener commutating diode.
Logic for this option is:
• E7 or E8 at XB port energized = system pressure A to PCOR only,
• F7 or F8 at XA port energized = system pressure B to PCOR only.
See TA option for the PCOR operation in T* controls.

Overview

Module N of the motor's order code indicates circuit options affecting features such as BPD and PCOR.
These are explained below. The pressure required to shift the motor varies with system pressure and by
frame size.

C0/C3 3

The C0 or C3 order code requires an external hydraulic signal into port XA or XB while draining the
opposite port. Signal pressure into port XA shifts the spool so only system pressure A is fed to the 4-way
valve for servo supply and to the sensing piston. Signal pressure into port XB shifts the spool so only
system pressure B is fed to the 4-way valve for servo supply and to the sensing piston. The C0 code is for
internal servo supply and the C3 code is for external servo supply with a plug at U5.
11009442 • Rev CA • January 2015