TT1000 – Tower Resistance Tester

The TT1000 is a 4-terminal test meter designed to measure the earth resistance of steel transmission towers or steel poles that are interconnected with an overhead lightning shield wire. It is important to measure tower earth resistance in order to design and determine the lightning protection performance of the power system. The TT1000 operates at a high frequency which results in the overhead earth wire appearing as a high impedance. This means the influence of parallel towers or poles is reduced.

Specifications:

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Range: 0.0 Ω – 757 Ω

Auto ranging with two ranges 0-19.4Ω and 0-757Ω. For very high earth impedance measurements our ET1000 soil resistivity tester is recommended.

Resolution: 0.5 Ω, with 2% FSD accuracy

Higher resolution of 0.1Ω is available on request at time of purchase

Input impedance: 1 MΩ

High input impedance ensures the effect of remote electrode impedance is minimized. In addition the front end circuit has been carefully designed to ensure minimal parasitic capacitance in the order of a few pF.

Output current: 33.6mA RMS

The exact test current depends on impedance of C probe circuit, with lower impedance resulting in higher currents. To ensure lowest measurement error higher, a test current is recommended this can be aided with the addition of multiple remote electrodes for the C probe circuit.

Output voltage: 25 V RMS max

The exact test voltage depends on impedance of C probe circuit, with lower impedance resulting in lower voltages. The output impedance is 757Ω.

Test frequency 225Hz & 40-80kHz with Auto Scan

The TT1000 offers two different test modes; high frequency scan mode and low frequency mode. In low frequency mode a fixed 225Hz test frequency is used, this gives similar results to industry standard meters such as our ET1000 which operates at 128Hz, this is useful in applications where a exact low frequency value is required. The high frequency scan mode is useful in applications where overhead earth wire effects must be minimized. In this mode the TT1000 automatically undertakes measurements at 40, 50, 60, 70 and 80kHz and then undertakes a linear interpolation, using a line of best fit algorithm to calculate the equivalent 128Hz value. For best measurement results a shielded cable is recommended for the C probe remote electrode circuit when operating in this mode.

Shielded cable drive connection

The C2 (remote current injection port) is a high quality two pin Lemo jack offering a shield drive. The use of a shield connection greatly reduces the effect of measurement error through unwanted radiated emissions coupling between the P probe circuit and the C probe circuit. The use of shielded 50Ω coax cables has been found to give the best results in our own product testing.

Display Reflective graphical monochrome LCD

The LCD offers a resolution of 128×64 pixels with a display size of 55x64mm.

Integrated Li-Ion battery

The integrated 11.1V/7.8Ahr battery pack offers a run time of approximately 16hrs. Auto power off converses battery power during periods of inactivity. The unit includes an integrated battery management system which can be charged by the supplied 15VDC 2A plug pack (center positive) with universal mains input

Easy Portability

The TT1000 includes a carry handle for easy transport and weighing only 2kg it is easy to carry around unaided. The unit measures 270x110x250mm so can easily be placed in a equipment box for easy transport.

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Support

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