Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C-Frame) - ForGe Control - Manual (Page 342)

342 Rockwell Automation Publication 7000L-UM301D-EN-P - June 2014
Chapter 5 Component Definition and Maintenance
Dissolved ionized solids and gases can be removed by using ion exchange resins.
Such resins attract ions in the water replacing them with H
+
and OH
-
ions,
which ultimately join to form water. Ion exchange resins are synthetic polymers
with several ion exchange sites attached to the surface. The ion exchange resins
gradually lose their effectiveness and need to be replaced or recharged.
It is imperative that iron- and chloride-free ethylene glycol is used. This is pure
ethylene glycol without corrosion inhibitors and other additives, which increase
the conductivity of the coolant. In addition, de-ionized water may be added to
the system for top up. Distilled water can only be used when no de-ionized water
is available, and when it is necessary to run the drive on line. Using distilled water
will significantly reduce the life of the ion exchange resin, and also reduce the life
of mesh filters.
Maintaining Coolant Ratio
Mixing pure ethylene glycol and de-ionized water produces the coolant used as
the cooling medium in the liquid-cooled PowerFlex 7000L Medium Voltage “C”
Frame drive. During operation, the concentration of pure ethylene glycol and de-
ionized water may change due to fluid leakage or evaporation; therefore, the
freezing point of the coolant may not be correct. The following instruction detail
the steps required to record and correct the freezing point of the coolant mixture.
Required items:
• Glycol and battery tester (Part No. 80025-862-01)
• De-ionized water, 19 L (5 gal) container (Part # 80025-784-60)
• Pure ethylene glycol, 19 L(5 gal) container (Part # 80025-784-61)
1. Measure and record the reservoir coolant freeze point using the Glycol and
Battery Tester.
2. If the freezing point of the coolant is at -45 °C (-50 °F) ±2 °C, correction is
not required.
3. If correction is required, then follow the remaining steps.
4. Water freezes at 0 °C (32 °F) and pure ethylene freezes at -13 °C (8.6 °F),
but mixtures of the two freeze at lower temperatures. For example, a 50/50
mixture by weight of ethylene glycol and water freezes at -36 °C (-33 °F).
The addition of ethylene glycol to the mixture will lower the freezing
point. Adjust the freeze temperature of the coolant mixture to -45 °C
(-50 °F) using this method.
5. Add either substance in small quantities and measure the freezing
temperature after each addition until desired freezing temperature is
achieved.
TIP Do not recycle the de-ionizing cartridge because it has been contaminated by
ethylene glycol and would contaminate the recycling facility.