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Assemble the Acoustic Stack
Converter Duty Cycle and Cooling
Converter performance and reliability can be adversely affected if the converter is subjected to
temperatures in excess of 140° F (60° C). The converter front driver temperature should not
exceed 122° F (50° C). To prolong converter life and maintain a higher degree of system reliability,
it is advisable to cool the converter assemblies with a directed stream of clean. dry, compressed
air, particularly if your application calls for continuous ultrasonics operation. Converter cooling is
especially critical in 40kHz applications.
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i
NOTE
Additional heat will be generated if the converter-booster-horn interfaces need reconditioning.
Be sure the stack is in good condition and properly assembled.
Two types of converters are normally used with Branson equipment:
• R-type equipped with a barbed cooling nipple that accommodates 1/16 in. I.D. flexible
tubing to direct cooling air to the interior of the converter assembly.
• J-type equipped with holes in the perimeter of the top and bottom plates to provide chim-
ney convection cooling, If additional cooling is required for this type of converter, a
directed orifice must be placed under the converter.
Two procedures can be used to determine if a converter is operating at a temperature that is too
high. In both cases, determinations should be made immediately after substantial machine oper-
ation and without power applied to the horn.
• Using a pyrometer (or similar temperature measuring device), tape the probe on to the
outer shell of the converter assembly. Wait for the probe to reach the the temperature of
the shell. If the temperature is120° F (48° C) or higher, a cooling air stream is required.
• If a temperature measuring device is unavailable, use your hand to feel the shell of the
converter. If the converter is hot to the touch, a cooling air stream is required.
If converter cooling is required, use the following procedure:
1. Start with a 50 psi air source (or higher) from a 0.060 in. orifice (I.D.). On a J-type
converter, direct the air upward from the bottom of the assembly.
2. Perform a run of welding operations.
3. Immediately after completing the run, check the converter temperature.
4. If the converter is still too hot, increase the diameter of the orifice in small increments
until the temperature falls within the safe operating ranges described in Table 17.
A 0.060 in. orifice at 50 psi will result in a reading of 80 cubic feet per hour. This should be sufficient
to cool most applications requiring an air stream. In continuous welding operations, or applications
with longer duty cycles, it may be necessary to cool the horn as well as the converter. Horns
require cooling because of the cumulative residual heat that is transferred from contacting the
workpiece.
48
100-214-226 Rev. 10
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