DyneSystems DS820F - PAU MAX CURRENT ADJUSTMENT; Procedure for Max Current Adjustment

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Product Warranty

APPENDIX A: PAU MAX CURRENT ADJUSTMENT

Only qualied personnel should adjust the PAU Field Current without assistance

from Dyne Systems Personnel

Coolant must be owing during this procedure

All PAUs should be set up for the dynamometer’s “hot amps” current rating.

NOTE: The dynamometer does not need to be spinning during this procedure.

To ensure proper control of the dynamometer and, more importantly, to protect the

coil from damage, the PAU needs to be adjusted to match the characteristics of the

dynamometer coil. The DS820F PAU has a Max Current adjustment potentiometer (P3).

Since dynamometer coil characteristics vary greatly depending on many factors, it is difficult

to preset this adjustment at the factory. It is important that after all connections are made,

the Max Current adjustment be performed.

When rst powering on the PAU, the LCD splash screen shows a current value of 15, 30, 50,

or 100 A. This displayed value represents the maximum current that the PAU is capable of

delivering, it does not represent the actual setting of the current limit.

After enabling the PAU, the LCD display will show the eld current that is being applied to the

dynamometer. Use this value for making all adjustments.

PAU:Ok Off

X% X.XA

PAU:Ok - Signies everything is okay, or else the word Fault is displayed (refer to

Wall and Rack Mount Troubleshooting Guide, Table 8.1, page 26).

Off - PAU is not enabled

X% - Percentage of command signal (0% = 0VDC or 0mA; 100% = 10VDC or

20mA)

X.XA - Amount of current being applied to coil

The max current setting is preset at the factory to either the minimum setting or an

approximate match to the dynamometer that was specied at the time of sale. In either

case, use the following procedure to check or adjust the max current setting:

1. Power OFF the PAU.

2. Turn potentiometer P3 (Figure A-1) on the DS820F board fully counter-clockwise

(minimum eld current setting).

3. Ensure that the dynamometer coolant is owing and all safeties are met or jumped out.

Dyne Systems • DS820F PAU