TWXFZ 140266, TWXFZ 140316, TWXFZ 140376
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Vishay Draloric
GUIDELINES
ELECTRICAL DATA AND GUIDELINES
• The main physical and electrical characteristics of the capacitors and ceramic materials used, are listed in the tables on the
general section and in the individual datasheets
• The continuous limit values of voltage, current, and power given in the diagrams must be observed.
• The rated voltage given in the tables is the peak value of the sinusoidal AC voltage or the sum of the DC and peak AC voltages
for which the capacitor is rated under continuous operation.
• The rated current in the tables is the effective value of the sinusoidal current for which the current paths of the capacitor are
designed.
INSTALLATION
• Watercooled pot capacitors (TWXFZ 140266, TWXFZ 140316, TWXFZ 140376) are designed to be installed in a vertical
position, connecting fittings of the watercooling system downside. Model 1 and Model 2 allows a flexible, 90° turned mounting
position of the capacitor. For large generators requiring multiple capacitors we recommended a circular mounting pattern for
optimum circuit performance.
• When capacitors are connected in parallel, care should be taken to mount the top electrodes of the capacitor away from the
RF bus bar to minimize the effects of stray electromagnetic fields. The capacitors elements must not exceed a temperature
of more than +100 °C.
• The electrical connection to the inner electrode must be flexible in order to prevent the generation of the physical forces which
could damage the capacitor elements. Such forces are often generated by the dimensional differences resulting from the
normal physical tolerances of the capacitors. The capacitor’s inner electrode connector must not be used as a mechanical
support for other devices or components.
COOLING
• The cooling system is designed to operate at a maximum water pressure of 4 bars (58 psi).
• The position of water inlet and outlet is designed to be installed in a vertical position, connection fittings of the watercooling
system downside. This allows any air to escape from the unit. Horizontal installations require that both water connections be
at the top side of the unit. To preserve the capacitors from frost damages during the transport, we offer special models with
outlet screws for emptying the cooling water from the unit.
• The minimum water flow rates specified in the tables must be observed. When using antifreeze mixtures, the flow rate should
be increased by at least 20 ꢀ.
• The cooling system is designed to have a water temperature increase of < 10 °C (water inlet to water outlet) when the capacitor
is operated at full rated power and the minimum water flow rate. A water intake temperature of 30 °C is recommended. If
the cooling system of several capacitors is connected in series, the intake temperature of the coolant must not exceed 50 °C
for any capacitors.
• The pressure drop in a series connected cooling system is small. The table below illustrates the effects upon water flow rates
as a function of the number of series connected typical watercooled capacitors in the system with a constant intake water
pressure of 3 bars (43.5 psi).
Number of cooling systems in series
Water flow rate (liters/minute)
1
2
3
4
5
13.0
3.43
10.5
2.77
8.5
7.3
6.0
Water flow rate (US-gal./minute)
2.24
1.92
1.58
• Intake water temperature fluctuations in excess of 3 °C/s must be avoided to prevent damage to the capacitor elements.
• A coolant temperature rate monitor must provide a fail-safe on / off power control for the RF equipment.
• Normal tap water or de-mineralized water may be used for cooling. The water must be reasonably free of CaCO3 and clear of
foreign particles or milkyness. The pH-value of the coolant should between 6 and 8.
Revision: 11-Sep-15
Document Number: 22132
4
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