Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C-Frame) - ForGe Control - Manual (Page 341)

Rockwell Automation Publication 7000L-UM301D-EN-P - June 2014 341
Component Definition and Maintenance Chapter 5
Figure 285 - Cleaning the Strainer
Coolant
The cooling fluid is a mixture of de-ionized water and ethylene glycol. De-
ionized water has been purified of most ionized solids and has very low
conductivity. The ethylene glycol is an iron- and chloride-free type and also has
low conductivity.
Water is an active solvent and gathers contaminants from everything it contacts.
In nature, ionized solids such as Sodium (Na
+
), Calcium (Ca
+2
) and chloride
(Cl
-
) are stripped from rocks and soil by water. Also found in water are organic
molecules from decaying debris, bacteria and microbes that normally grow in
water, and dissolved ionized gases such as chlorine (Cl
2
) and carbon dioxide
(CO
2
).
Conductivity is primarily the result of ionized solids and gases in water. The
other materials in water contribute very little to electric current flow. When a
voltage is impressed on water, current flows by using the ionic molecules as
stepping stones for the current. Most bacteria and organic materials offer few
stepping stones for current, so if the ionized solids and gases are removed, the
water becomes relatively non-conductive.
To Pump P2
V1
V3
Strainer
STR1
V2
To Pump P1