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What is the best TTR for 3 phase transformers?

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    What is the best TTR for 3 phase transformers?

    I am in search of a 3-Phase TTR test set that can perform TTR testing on both three-phase and single-phase transformers. I mainly deal with 69kV to 12.47kV and 161kV to 69kV or 12.47kV. We currently use the Doble M-4100 to perform Doble Ratio tests on both single-phase and three-phase transformers. User-friendliness and ease of set-up is a must!

    Any advice or suggestions would be great! Thanks in advance.

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    Quote Originally Posted by Robertsj View Post
    I am in search of a 3-Phase TTR test set that can perform TTR testing on both three-phase and single-phase transformers. I mainly deal with 69kV to 12.47kV and 161kV to 69kV or 12.47kV. We currently use the Doble M-4100 to perform Doble Ratio tests on both single-phase and three-phase transformers. User-friendliness and ease of set-up is a must!

    Any advice or suggestions would be great! Thanks in advance.
    We use the Megger TTR 310 when we forget the capacitor for the 4100. Also have a few handheld units. I've used the Raytech single phase a few hundred times and it's nice. I expect the 3 phase would also do a fine job.

    Any TTR equipment out today should be easy to operate for a qualified tech.

    Ideally, you test at a higher voltage than what the case unit test sets can provide. What is driving the change away from the 4100?

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    Quote Originally Posted by rofo42 View Post
    We use the Megger TTR 310 when we forget the capacitor for the 4100. Also have a few handheld units. I've used the Raytech single phase a few hundred times and it's nice. I expect the 3 phase would also do a fine job.

    Any TTR equipment out today should be easy to operate for a qualified tech.

    Ideally, you test at a higher voltage than what the case unit test sets can provide. What is driving the change away from the 4100?
    Thanks for the reply! We have an antique handheld unit as well if we are forced to test in the rain or wet conditions. We get by just fine with the 4100 testing single-phase xfmrs, but we are installing more and more three-phase units. Typically, we have to cut corners, testing only a few taps of the LTC when testing with the single-phase unit because it takes so long. From what I've been around the three-phase units, they knock out a 32-step LTC in no time at all.

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    Quote Originally Posted by Robertsj View Post
    I am in search of a 3-Phase TTR test set that can perform TTR testing on both three-phase and single-phase transformers. I mainly deal with 69kV to 12.47kV and 161kV to 69kV or 12.47kV. We currently use the Doble M-4100 to perform Doble Ratio tests on both single-phase and three-phase transformers. User-friendliness and ease of set-up is a must!

    Any advice or suggestions would be great! Thanks in advance.
    Our office has used the below Vanguard for years, but when it fails, it fails dramatically. We rented the below Raytech and the techs using it loved it, once they figured out it will automatically jumper odd configured transformers internally to the test set (I unfortunately never saw it and cannot personally comment). The Vanguard will not automatically jumper but once you figure out the configuration in the back of the manual (appendix) the ttr ask what configuration number and will instruct when to jumper as you run the test.

    https://www.vanguard-instruments.com...meters/atrt-03

    http://www.raytechusa.com/products/t...mark-iii-250v/

    My recommendation is to rent the test sets, and get a feel for which one you prefer.

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    Quote Originally Posted by rofo42 View Post
    We use the Megger TTR 310 when we forget the capacitor for the 4100. Also have a few handheld units. I've used the Raytech single phase a few hundred times and it's nice. I expect the 3 phase would also do a fine job.

    Any TTR equipment out today should be easy to operate for a qualified tech.

    Ideally, you test at a higher voltage than what the case unit test sets can provide. What is driving the change away from the 4100?
    Megger TTR 310 is no longer in new production and has been updated to the TTRU3 model.

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    Quote Originally Posted by Kalbi_Rob View Post
    Megger TTR 310 is no longer in new production and has been updated to the TTRU3 model.
    I thought I saw the 310 was discontinued. Makes sense as the technician that had the test set has 40 years in with the company. That TTRU3 looks awesome. Doubt I'll use it any time soon.

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    We have a Tettex Winding Analyzer 2293. It Does TTR(one phase at a time unlike TTRU3) and winding resistance (both 3 phase) in the same unit. It's compact, light, and a huge time saver. I recommend.

    Update: I forgot to mention it also demagnitizes the windings. This could allow you to change up the order of testing allowing you to power factor and perform excitation on a confirmed demagnetized transformer.
    Last edited by test11; May 2, 2020 at 01:42 PM.

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    TTR

    You can perform multiple tests using the M4100. To perform all 33 taps on one phase of a three phase transformer takes about 15 minutes if you can operate the tap changer electrically. The M7100 can perform low voltage and high voltage TTR and you can setup to change the tap for you. There are advantages to performing TTR tests at high and low as both test methods have advantages and disadvantages.

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