Danfoss MCH Installation guide

MCH Control Handle

Instructions for Addition or Replacement of Parts

BLN-95-9057-1

Issued: April 2002

INSTALLING NEW CENTER SWITCH

1.Install cam with hub to the outside. (Do not tighten setscrew.)

2.Install switch so that the switch body is toward the radius side of the notch in the cam. (See Location of Radius.)

3.Move cam switch until roller is in notch of cam.

4.Tighten switch mounting screws to fasten switch.

5.SEE WARNING. Adjust cam to ensure switch is actuated when the handle is within 3° ±1° of neutral or detented position.

6.Tighten setscrew on cam.

7.SEE WARNING. Recheck actuating angle of CAM. If not within 3° ±1° of neutral or detented position, loosen CAM setscrew and readjust.

8.Wire as desired.

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Failure to calibrate switches within the specified angles may result in the switch being activated when the handle is not in the proper position. (Example: If the switch is a center off switch and is not calibrated per specifications, the machine function controlled by that handle may be activated when the handle is in the neutral position.)

INSTALLING NEW AUXILIARY SWITCH

1.Determine desired switching angle and mount switch.

2.SEE WARNING. Adjust switch to within ±1° of desired switching angle.

3.Tighten switch mounting screws. Do not adjust auxiliary switches by moving cam, as this will destroy center switch adjustment.

4.Wire as desired.

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Failure to calibrate switches within the specified angles may result in the switch being activated when the handle is not in the proper position. (Example: If the switch is a center off switch, and is not calibrated per specifications, the machine function controlled by that handle may be activated when the handle is in the neutral position.)

REPLACING EXISTING SWITCHES

1.Identify and record wire positions.

2.Remove wires from switch.

3.Remove switch. (Do not remove cam.)

4.SEE WARNING 1. Install switch, as described above.

5.SEE WARNING 2. Install wires in the original positions.

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1.Failuretocalibrateswitcheswithinthespecifiedangles may result in the switch being activated when the handle is not in the proper position. (Example: If the switch is a center off switch, and is not calibrated per specifications,themachinefunctioncontrolledbythat handle may be activated when the handle is in the neutral position.)

2.Failure to replace wires or electrical components to theiroriginalpositionsmayresultinanelectricalfailure whichcouldburnoutthehandleorvalve,orcausethe functiontobereversedfromitsoriginalaction,orinthe elimination or bypassing of a function.

BLN-95-9057-1

REPLACING SPUR GEAR

1.Identify and record wire positions of switches.

2.Remove wires from switches.

3.Remove cam assembly.

4.Remove switch side plate.

NOTE: On friction-held handles, take precautions to prevent the loss of the detent spring and ball.

5.Remove spur gear.

6.Install new spur gear by aligning teeth with gear segment. (Do not tighten setscrew.)

7.Electrically null potentiometer. (See “Replacing Potentiometer”, Step 13.)

8.Tighten spur gear setscrew.

9.Replace detent spring and ball. (Friction-held handles only.)

10.Replace switch side plate.

SEE WARNING 1 below. If the handle has the center lock option, replace the side plate and check the center lock action. If it does not function, readjust the side plate and recheck until it works properly.

SEE WARNING 2 below. Check for free handle movement in both directions. If it does not function, readjust the side plate and recheck until it works properly.

11.Adjust switches. (See above.)

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1.Failure to calibrate the center lock function may result

in the handle passing through the center position without locking.

2.Failuretoensurefreehandlemovementinbothdirections may result in limited movement in one direction, or (if spring returned) may cause the handle to stick in one direction.

LOCATION OF THE RADIUS

LOCATION OF THE #2 SWITCH

CAM	RADIUS
ASSEMBLY	RADIUS	#2
ASSEMBLY

		#1
SWITCH
BODY
		COMMON
		NORMALLY CLOSED
	1323	NORMALLY OPEN	1326
SINGLE POTENTIOMETER TERMINAL		DUAL POTENTIOMETER TERMINAL

NO. 1

NO. 2

	1	2	3	1	3		4	6
		2			2			5
+	A	B	—		+	A	B	—

(2)(3)

1324

1325

BLN-95-9057-1

REPLACING POTENTIOMETER

1.Identify and record wire positions on switches and potentiometer.

2.Remove wires and switches from potentiometer.

3.Remove cam assembly.

4.Remove switch side plate.

NOTE: On friction-held handles, take precautions to prevent the loss of the detent spring and ball.

5.Remove spur gear.

6.Remove potentiometer.

7.Install new potentiometer. (Do not tighten.)

8.Install spur gear. (Do not tighten.)

9.Adjust gear mesh by sliding potentiometer toward gear segment to obtain minimum backlash.

10.Tighten potentiometer.

11.SEE WARNING1 below. Rewire potentiometer and switches to original positions.

12.If the control handle has (2) switches and there is a resistor in line with the common terminal of the #2 switch, disconnect the common lead. (See Location of #2 Switch.)

13.SEE WARNING 2 below. Electrically null potentiometer.

If the handle is a bi-directional device with a single potentiometer,nullthepotentiometerusingthefollowing method (see Single Potentiometer Terminal).

Place the handle in the center or detented position. If the handle has a center off switch, connect a jumper wire from “+” on the terminal strip to potentiometer terminal #1. Connect the power lead from the machine to “+” on the terminal strip and the ground lead from the machine to “-” on the terminal strip. Using a voltmeter, connect the “+” on the meter to the “A” on the terminal strip, and the “-” on the meter to “B” on terminal strip. Rotate the potentiometer until the meter reads 0±.1 volts. Tighten setscrew on spur gear. Recheck the value at the center position. If not in specification, repeat the nulling procedure. If a jumper wire was used between potentiometer terminal #1 and “+”, remove it.

If the handle is a bi-directional device with dual potentiometers, null the potentiometers using the following method (see Dual Potentiometer Terminal).

the “+” lead from the meter to potentiometer terminal #2. Divide the original voltage by 2. Turn the #1 potentiometer shaft until the meter reads that value. Tighten setscrew on spur gear. Move the “+” lead from the meter to “A” on the terminal strip, and the “-” from the meter to “B” on the terminal strip. Rotate the #2 potentiometer shaft until the meter reads 0±.1 volts. Tighten setscrew on spur gear. Move handle to full stroke in each direction, noting voltages. If the full stroke voltages are not within 10% of each other, loosen setscrew on potentiometer #1, rotate the shaft slightly, tighten the setscrew, and renull potentiometer #2. Repeat if necessary. If a jumper wire was used between “+” and potentiometer terminal #1, remove it.

If the handle is a uni-directional device, null the potentiometer using the following method (see Single Potentiometer Terminal).

Rotate the handle full clockwise when viewed from the potentiometer side. If the handle has an end off switch, jumper from the “+” on the terminal strip to potentiometer terminal #3. Connect the power lead from the machine to the “+” terminal, and the ground lead from the machine to the “-” terminal. Using a voltmeter, connect the “+” from the meter to potentiometer terminal #2, and the “-” from the meter to the “-” on the terminal strip. Rotate the potentiometer shaft slowly to decrease the voltage. When the meter reads 0 +.2/-.0 volts, tighten setscrew on spur gear. Recheck reading. Repeat procedure if necessary. If a jumper wire was used between “+” and potentiometer terminal #3, remove it.

14.If the common lead from switch #2 was removed, reconnect it. (See Location of #2 Switch.)

15.Replace detent spring and ball.

16.SEE WARNINGS 3 AND 4 below. Replace switch side plate.

17.Adjust switches. (See Installing New Center Switch and Installing New Auxiliary Switch.)

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1.Failure to replace wires or electrical components to theiroriginalpositionsmayresultinanelectricalfailure whichcouldburnoutthehandleorvalve,orcausethe functiontobereversedfromitsoriginalaction,orinthe elimination or bypassing of a function.

2.Failure to null potentiometer may result in an uneven output in each direction. The machine function controlled by the handle may be faster in one direction than in the other.

3.Failure to calibrate the center lock function may result

in the handle passing through the center position without locking.

4.Failuretoensurefreehandlemovementinbothdirections may result in limited movement in one direction, or (if spring returned) may cause the handle to stick in one direction.

BLN-95-9057-1

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