Primary copper tubing
Graham Armitage, Tue Jun 24 2014, 09:06PMAt what primary current levels would one switch from 1/4" to 3/8" copper tubing to limit heating and other resistive losses? Assuming 80kHz Fres. Obviously 1/4" is cheaper and gives a tighter wound primary, but 3/8" is significantly larger circumference and hence greater conductivity given the small skin effect of copper. Is there a formula or rule of thumb folks use?
Re: Primary copper tubing
HV Enthusiast, Wed Jul 02 2014, 01:37PM
Good question.
However, you cannot even go by copper OD diameters. There is a huge variation in the cross-sectional area of copper tubing of the same OD. Just Lowes itself sells 3/8" copper tubing with a variety of wall thicknesses, some which aren't even readily apparent. So wall thickness needs to be taken into account as well.
Generally, for small coils (say 1-2kW max, i'll use 1/4" OD copper), and then work my way up. Note, that for high power DRSSTCs, you may even need water cooling on the primary coils depending on the currents and duty cycles you are running.
HV Enthusiast, Wed Jul 02 2014, 01:37PM
Good question.
However, you cannot even go by copper OD diameters. There is a huge variation in the cross-sectional area of copper tubing of the same OD. Just Lowes itself sells 3/8" copper tubing with a variety of wall thicknesses, some which aren't even readily apparent. So wall thickness needs to be taken into account as well.
Generally, for small coils (say 1-2kW max, i'll use 1/4" OD copper), and then work my way up. Note, that for high power DRSSTCs, you may even need water cooling on the primary coils depending on the currents and duty cycles you are running.
Re: Primary copper tubing
Graham Armitage, Wed Jul 02 2014, 03:31PM
Ok, I am planning on around 500A peak primary current (should be less than 2kW input power). I thought 1/4" would suffice but wanted to check. Thanks
Graham Armitage, Wed Jul 02 2014, 03:31PM
Ok, I am planning on around 500A peak primary current (should be less than 2kW input power). I thought 1/4" would suffice but wanted to check. Thanks
Re: Primary copper tubing
HV Enthusiast, Wed Jul 02 2014, 05:55PM
1/4" OD tubing is fine for this.
HV Enthusiast, Wed Jul 02 2014, 05:55PM
1/4" OD tubing is fine for this.
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