---
title: Single Phase & Three Phase Ratiometers | Raytech USA Help Center
description: "Models: TR-Junior, TR-1, TR-1P\nTR-Spy, Mark II, Mark III, Mark III 250v"
---

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1. [Raytech USA Help Center](https://support.raytechusa.com/migration)
2. [Single Phase & Three Phase Ratiometers](https://support.raytechusa.com/migration/single-phase-three-phase-ratiometers)

# Single Phase & Three Phase Ratiometers

 Models: TR-Junior, TR-1, TR-1P TR-Spy, Mark II, Mark III, Mark III 250v

## TR-Mark III 250V

- [How to do a system check?](https://support.raytechusa.com/migration/how-to-do-a-system-check)
- [Can I control the TR-Mark III 250V remotely from the LTC Controller?](https://support.raytechusa.com/migration/can-i-control-the-tr-mark-iii-250v-remotely-from-the-ltc-controller-instead-of-going-back-and-forth-from-the-ltc-controls-to-the-ttr)

## TR-1

- [My TR-1 / TR-1P is displaying "System Protected"](https://support.raytechusa.com/migration/my-tr-1-/-tr-1p-says-system-protected)
- [I do not see a "Go" button with the TR-1 or TR-1P](https://support.raytechusa.com/migration/i-do-not-see-a-go-button-with-the-tr-1-or-tr-1p)

## General

- [Can I use a Raytech Transformer Ratiometer to test CT Ratio also?](https://support.raytechusa.com/migration/can-i-use-the-raytech-ttr-to-test-ct-ratio-also)
- [My system won't power on.](https://support.raytechusa.com/migration/my-system-wont-power-on)
- [I can't see the characters on my screen or the screen is all black.](https://support.raytechusa.com/migration/i-cant-see-the-characters-on-my-screen)

- [Frequently Asked Questions](https://support.raytechusa.com/migration/frequently-asked-questions)
- [Capacitance / Dissipation Factor / Power Factor](https://support.raytechusa.com/migration/capacitance-dissipation-factor-power-factor)
- [Low Resistance](https://support.raytechusa.com/migration/low-resistance#main-content)
  
  
  
  
  
    - [Micro Centurion II (MC2)](https://support.raytechusa.com/migration/low-resistance#micro-centurion-ii-mc2)
    - [Kelvin Spike Probes](https://support.raytechusa.com/migration/low-resistance#kelvin-spike-probes)
- [mini-ATOS](https://support.raytechusa.com/migration/mini-atos)
- [Single Phase & Three Phase Ratiometers](https://support.raytechusa.com/migration/single-phase-three-phase-ratiometers#main-content)
  
  
  
  
  
    - [TR-Mark III 250V](https://support.raytechusa.com/migration/single-phase-three-phase-ratiometers#tr-mark-iii-250v)
    - [TR-1](https://support.raytechusa.com/migration/single-phase-three-phase-ratiometers#tr-1)
    - [General](https://support.raytechusa.com/migration/single-phase-three-phase-ratiometers#general)
- [Winding Resistance](https://support.raytechusa.com/migration/winding-resistance)

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