Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C-Frame) - ForGe Control - Manual (Page 343)

Rockwell Automation Publication 7000L-UM301D-EN-P - June 2014 343
Component Definition and Maintenance Chapter 5
There are two possible causes of water loss in the drive:
Evaporation – Up to 99.5% of liquid lost to evaporation is water because of the
chemical properties of the substances in the mixture.
Leaks – Glycol and water are lost proportionally depending on the concentration
of the substances in the mixture. For example, if the mixture is 60% glycol and
40% water, then any leakage will contain the same proportions of the liquids.
To rectify the problem, add small quantities of water. Measure the freeze
temperature of the coolant after each addition and continue adding until the
desired freezing temperature is achieved.
Leakage Checks
When repairing leaks or working on the stack assemblies, it is highly
recommended that several layers of industrial-grade absorbent pads be placed on
top of the middle and lower stacks to prevent any coolant spills from falling down
on to the lower components, specifically the printed circuit boards.
Most leaks will be visible in the first 30 minutes, and once the system begins to fill
and pressurize, you should be constantly inspecting all fittings and connections
for drips. It is best to have help in checking the inverter and rectifier section, and
the DC Link cabinet. An absorbent cloth is ideal for checking that the coolant is
actually leaking and is not just remnants of the repair.
If a leak is a visible at the threaded joint of a stainless steel fitting and a CPVC
(plastic) pipe, the leak can often be repaired by tightening the joint.
Use the following values of torque when tightening stainless threaded fittings
into CPVC.
If a leak persists, it will be necessary to drain the system, disassemble the threaded
joint, clean the threads and reassemble with a generous amount of Teflon paste
applied to the threads.
No matter how well you drain the system with the pumps, be aware that there will
be liquid in the tubes, manifolds, and chill blocks. This requires special care in
IMPORTANT It is better to have more water than glycol in the mixture because
water is a better thermal conductor than glycol.
Thread Size Torque N•m (lb•ft) Typical Wrench Size
l/4 inch NPT 9,5 N•m (7.0 lb•ft) 15 mm (9/16 in.)
3/8 inch NPT 9,5 N•m (7.0 lb•ft) 19 mm (3/4 in.) and 26 mm (1 in.)
1/2 inch NPT 27 N•m (20 lb•ft) 29 mm (1-1/8 in.)