HighTest TRAN-203B

The model name numbers refer to its two primary power sources:

• 20A DC (Winding Resistance):

  • It injects up to 20 Amperes of DC current to measure the resistance of the copper windings.

  • Why this matters: 20A is significantly more powerful than standard handheld testers (which usually do 1A–5A). The higher current saturates the transformer core much faster, stabilizing the reading quickly on large distribution and power transformers.

• 250V AC (Turns Ratio):

  • It generates up to 250 Volts AC to test the Turns Ratio (TTR).

  • Why this matters: Most basic TTR testers only output ~40V or 100V. Having 250V is critical for testing large power transformers (especially those with high excitation currents) because lower voltages often result in “Ratio Errors” or unstable readings on big iron cores.

• One-Time Connection: You connect the High Voltage (H) and Low Voltage (X) leads once. The unit automatically switches internally between TTR and Winding Resistance modes without you having to climb the ladder to move clips.

• Demagnetization: After performing a DC resistance test, the transformer core is left magnetized (which is dangerous and causes high inrush current upon energization). The TRAN-203B has an automatic Demagnetization cycle to clear this.

• Battery Powered (The “B”): The “B” in the model name typically indicates it includes an internal Li-Ion Battery. This allows you to test in the field without needing a generator or extension cord immediately.

• Built-in Printer: It has a thermal printer on the front panel to print results immediately for the customer/site manager.

• Tap Changer Testing: It can measure resistance across all taps (Heat Run test) and verify the On-Load Tap Changer (OLTC) operation

Manual ⇓

Datasheet ⇓