Austin Insulators Base Insulator for Guyed Radio Towers and Masts

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Austin Base Insulators for Guyed Radio Towers and Masts

Austin Base Insulators for Guyed Radio Towers are oil filled and use ceramic in compression to bear the tower download.

In these bases, the resistance to shear load is derived from the compressive load and preload applied to the base.

In addition to the standard range, designs can be provided for custom applications with extremely high electrical and mechanical working loads as well as high seismic load conditions. Special exact fit replacement bases, as substitutes for insulators by other manufacturers, are also available.

Oil filled to eliminate Radio Frequency loss due to water condensation on internal surfaces. Additional benefits are elimination of ‘hot spots’ and easy detection of porcelain failure.

Smooth insulator finish minimizes leakage and flashover due to surface contamination.

Items listed are types recommended for new construction. Previously listed Austin types are available for replacement purposes.

Insulators for higher mechanical and electrical loads are available. Please call, write, or e-mail stating your requirements.

All insulators are supplied with adjustable lightning gap.


Allows for a minimum Safety Factor of 3. The drip wet figures above are a minimum achieved with the insulator standing directly on the ground plane. Higher voltages can be expected with the insulator installed on a pier. Recommended Operating Voltage is 60% of Drip Wet Withstand Voltage. Insulators A-4197-L and A-4722-B are designed to be rigidly attached to the mast and are free to rock on their mounting plates. All other insulator types attach to the mounting pier or pedestal provided by the customer and the mast is left free to rock on the insulator rocking plate supplied. Insulators A-4197-L and A-4722-B have cemented ends. All other types are supplied with temporary tie-rods which are removed ONLY when mast erection is complete. All insulators with the exception of the A-4197-L can be fitted with a high voltage rainshield as an optional extra to improve the voltage rating.

Technical Specification

Technical Specification


Insulator Type Number of Elements Maximum Recommended Working Download
(note 1)
Permissible Shear as a Percentage of Download 1 minute Drip Wet
Withstand at 100kHz;
Voltages KV RMS
(notes 2 & 3)
Standard Rainshield High Voltage Rainshield
A-4197-L 1 40,000 lb
18,140 kg
6.0 28 N/A
A-4722-B 1 80,000 lb
36,280 kg
6.0 39 53
A-0881 1 150,000 lb
68,100 kg
5.3 67 95
A-0729 1 200,000 lb
90,800 kg
5.8 67 95
A-0167 1 270,000 lb
122,500 kg
6.2 67 95
A-3663-B 3 375,000 lb
170,100 kg
3.2 71 99
A-4447-B 5 625,000 lb
283,500 kg
3.1 71 99
A-3820-R 8 1,000,000 lb
453,600 kg
3.0 71 99
A-4544 12 1,500,000 lb
680,400 kg
2.9 71 99
A-4598 21 2,500,000 lb
1,134,000 kg
2.8 71 99


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