Learn it. Wire it. Energize it. Check your work.
Built by a working journeyman lineman for linemen and their apprentices. The XFMR Lab simulates distribution transformer banks driven by your own wiring — the metering, fusing, and faulting all behave the way you'd expect in the field.
NEW IN 2.0 — BUILT-IN TRANSFORMER TRAINING (Replacing XFMR INFO)
Six guided lessons take you from "what's a transformer?" to wiring a 3-pot bank:
• Start Here — What is a Transformer?
• Dual H Bushings — The Two Wirings & the Nameplate
• The Tap Changer — One Pot, Multiple System Voltages
• Three-Phase — The Three Phases and How They're Related
• Bank Identification — Delta or Wye, Open or Closed
• Your First Bank: Delta-Wye Closed (120/208)
• More lessons on the way!
Work the lessons in order, or jump straight to the labs.
ALSO NEW IN 2.0
• The Sandbox (Beta) — wire anything from scratch in a COMPLETELY-customizable lab, with live, vector-based voltage and fault logic baked in.
• Death Traps — scenario-based transformer traps linemen run into — and how to navigate them safely.
• A brand-new look across every lab — new graphics, sharper, faster, & easier to read in the field.
• Voltmeter you can now drag with two fingers; readings update as the leads move.
• Parallel the secondary coils by hand in wye secondary labs
• Stats that track lab completions, quiz scoring and for-fun stuff like the number of fuses you've blown.
• User Customizations - the user can now alter the spec of their labs; from grounding to parallel coil cutover-direction, requiring the 4th cutout, tap changer implementation and more.
• 2.0 is FREE for everyone who already owns XFMR Lab — thank you for years of feedback and encouragement.
WHAT YOU GET
Single Phase — Single Bushing · Dual Bushing
Three Phase (closed) — Delta-Delta · Delta-Wye · Wye-Delta · Wye-Wye
Three Phase (open) — Open Delta-Delta · Open Wye-Delta
Misc — Paralleling · 4th Cutout · Death Traps (6 Scenarios)
Advanced — Straight 480 · 240/480 · 277/480 · Corner-Grounded 240/480 · Wye-Wye 5-Wire (120/240 + 120/208) - all now able to be wired up Wye AND Delta on the topside
The Sandbox (Beta)
EVERY FUTURE UPDATE IS FREE - THE APP IS A ONE-TIME PURCHASE. I'm always working on new updates.
TOOLS & REFERENCE
• Volt, ohm and rotation meters with real behavior
• Nameplate, secondary coil and tap changer animations
• Reference diagrams for every standard bank
Learning Mode walks apprentices through every wrong-connection check. Journeymen and experienced users can keep this turned off if they'd like.
QUIZZES
• Classic Quiz — Select each lab you want in your quiz - with graded scoring across each lab.
• Advanced Quiz — You're provided with the job-site info and need to pick the right nameplate and coil setup, then wire it.
• Bank ID - A beginner's quiz tied into the new XFMR Training lesson plan. The user is provided with different primary and secondary wirings and must correctly identify them.
Used by 30,000+ linemen since 2021.
Questions? Suggestions? Reach me at info@digitalapprentice.net
How about being able to select transformers from a list (a.k.a. transformer dock)so to be able to bank subtractive and additives transformers. Also, would like to be able to tie three phase secondary legs on the open secondary lines below transformers instead of tying secondary bushings then dropping one leg to secondary. Just suggestion to make people understand the beast. UPDATE! The developer has contacted me that they are already moving towards these improvements!!
Developer Response
Thanks for the review! I have thought about the option to select transformers from a list and being able to build a bank completely from scratch. I have plans to implement "advanced banks" in the future and this could be included in that!
Love the app but…
mmikemmike
Definitely some issues. I’ll wire up a bank correctly and it’ll tell me it’s wrong. I can delete my secondary’s and reconnect them exactly the same way and close the fuses again and it’ll say it’s right. Also, I’ll wire up a wye delta (for example) and it’ll say “this is a correct way to wire a delta delta bank” when obviously it should say wye delta. Lastly the app needs to be run with a horizontal screen but you can’t put the volt meter on the c phase secondary leads because of the layout. Still worth the $10 with the few issues it has
Developer Response
Thanks for the review! I haven't had any reports until now about the labs telling you it it's wrong and then tell you it's right when you wire it up the same way. Let me know which lab is doing that and I'll take a look! Info@digitalapprentice.net Also, thanks for catching the wrong wording! That'll be fixed in the next update! I also spent a lot of time trying to figure out the best layout for everything to fit on such a small screen and how to check C phase. Thanks again!
Almost perfect
Maxellis234
I’m using this app to practice my connections for my transformer class and it’s really really great well worth the 10$ but when I wire up a bank correctly it will tell me it’s wrong it only does this with the delta delta or the wye wye I will match them up perfectly with the image but still say it’s wrong I’ve even asked my teacher if they are wired correctly and he said yes. Once that gets fixed this app will be 5/5
Developer Response
Thanks for the review! Can you please send screenshots of this issue to info@digitalapprentice.net so I can address this? Thanks!
Great training reference!
Climbinsticks
This is a great app, let me just start with that.It would be great if you could build your own banks and check voltage and what not. The set diagrams are awesome but being able to play around with different connections would make it better. Also tap changer settings and info would also be a great addition.
Various Bug Fixes.
Version 2.0.5
The developer, Digital Apprentice LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
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Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
Seller
Digital Apprentice LLC
Size
67.8 MB
Category
Education
Compatibility
Requires iOS 16.0 or later.
iPhone Requires iOS 16.0 or later.
iPad Requires iPadOS 16.0 or later.
Mac Requires macOS 13.0 or later and a Mac with Apple M1 chip or later.