Detroit Diesel DDEC VI Application And Installation page 314

FEATURES
Example 2 – Two Torque Limits
The customer wants to hold the torque to 450 ft lbs (on an engine rated at 860 ft lbs) up to 6th gear
and up to 550 ft lbs up to 8th gear. The transmission operates with the ratios listed in Table 5-54.
Gear
5
Desired Gear Down Protection Ratio
6
7
8
9
10
*The low gear threshold is determined by taking the inverse of the gear ratios and choosing a value in
between the gears you want to limit.
Table 5-54 Transmission Ratios
The "torque factor" is determined by dividing the desired torque by the rated torque. The
"threshold" is determined by taking the inverse of the gear ratios and choosing a value in between
the gears you want to limit.
To summarize, the customer wants to limit torque up to the 6th gear to 450 ft·lb and 550 ft lbs up
to 8th gear. Estimate the "threshold" between 5th and 6th (0.32) and 7th and 8th (0.5). From 8th
gear on up, the full rated torque will be available.
Set "Gear Ratio for Gear Down Protection" to 0.32 and set the "Torque Factor for Gear Down
Protection to 0.52 (450/860). Set "Gear Ratio for High Gear Power" to 0.5 and the "Torque
Factor High Gear Power" to 0.64 (550/860).
5-102
Ratio
3.57
2.79
2.14
Desired Gear Ratio for High
Gear Power
1.65
1.27
1.00
7SA827 0701 Copyright © 2007 DETROIT DIESEL CORPORATION
Low Gear Threshold* CPC –
Output/Input Shaft Speed
0.280
Gear Down Protection Ratio Parameter
0.358
0.467
Gear Ratio for High Gear Power Parameter
0.606
0.787
1.0
All information subject to change without notice. (Rev. 01/07)