Twin Disc TA-90-8501, Operator'S Manual

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110
Twin Disc, Incorporated
Troubleshooting
Power Transmission System Operator’s Manual #1020510
Table 4 shows expected pressure values for the electric modulating valves tested
in troubleshooting Test 8. The oil temperature range is between 100° F and
180° F, and the system main pressure is 250 psi or less, and SAE 10W oil is
used. The pressure at an intermediate setting is not affected by the main supply
pressure, but will level off when main pressure is reached. The important things
to consider when testing a valve are that there should not be any pressure at
zero current, and full pressure when
100 is displayed. The orientation of the
axis of the valve coil with respect to the horizontal plane affects the
resulting pressure. The maximum pressure results when the coil axis is
vertical with the coil end up. Conversely, the minimum pressure results
when the coil axis is vertical with the coil end down.
A plot of pressure vs.
current should result in a reasonably smooth line from minimum current to
maximum current.
Table 4. Proportional Valve Pressure Chart
Current Pressure Pressure
% of full minimum maximum
0 0 0
5 0 0
10 0 0
15 0 0
20 0 0
25 0 0
30 0 15
35 3 29
40 10 46
45 30 70
50 52 90
55 74 110
60 93 129
65 112 148
70 135 170
75 155 189
80 177 210
85 195 230
90 218 246
95 230 255
100 241 255