Worksheet / Checklist

Control Transformer Sizing Worksheet

This worksheet is designed to capture the exact job details behind control transformer sizing so the next conversation can start from real data instead of guesses, missing nameplates, or half-complete notes.

Difficulty: IntermediatePosted: 2026-03-15

Quick answer

Use this worksheet to capture the field details that will decide whether the replacement, quote, or troubleshooting path is actually correct.

Table of contents

  1. What this worksheet captures
  2. When to use it
  3. Worksheet
  4. How to use it on site
  5. What to verify before sending it on
  6. Important verification notes
  7. Common mistakes
  8. FAQ

When this matters

This matters when a field tech, buyer, or panel builder needs to collect the right details for control transformer sizing before the job turns into a quote, replacement, or retrofit decision.

What this worksheet captures

This worksheet is built to capture the field details that usually decide whether control transformer sizing can move into a quote, replacement, or engineering review.

It is meant to keep the intake practical, consistent, and easier to hand off between maintenance, engineering, and purchasing.

  • primary voltage
  • secondary voltage
  • steady-state VA
  • largest inrush load
  • simultaneous loads

When to use it

Use it when the field information is incomplete, when multiple people are touching the job, or when the replacement path depends on details that are easy to miss over email or phone.

Worksheet

Fill this in on-screen or print the page and carry it into the field so the same core details make it back to engineering, sourcing, or quote review.

Field Value Notes
Primary voltage

Read the transformer nameplate or published datasheet and record the exact ratings shown there.

Value
Unit
Secondary voltage

Read the transformer nameplate or published datasheet and record the exact ratings shown there.

Value
Unit
Steady-state VA

Use the device burden data, coil inrush data, or the control bill of materials to capture the true transformer load.

Value
Unit
Largest inrush load

Use the device burden data, coil inrush data, or the control bill of materials to capture the true transformer load.

Value
Unit
Simultaneous loads

Use the device burden data, coil inrush data, or the control bill of materials to capture the true transformer load.

Value
Unit

How to use it on site

Work from the installed equipment first, then collect the ratings, environment, fit notes, and related components that change the actual buying decision.

Item What it means in practice Why buyers care
Core role Step voltage or current to a usable value for the control or measurement circuit This tells you why transformers appear in both power and signal discussions.
What engineers compare first primary and secondary values, burden, and protection strategy Those are the values that change the actual fit.
Typical supporting parts fuses, meters, power supplies, pilot devices, and analog inputs Transformers sit between the power system and the control system.
Common confusion Selecting by ratio alone and ignoring burden or protection The ratio is only part of the decision.

What to verify before sending it on

A worksheet is most useful when the captured values are checked for completeness before they move into sourcing or quote prep.

Important verification notes

Use the worksheet to structure the job, then confirm the final release path against the exact product-family data and installed conditions.

Common mistakes

  • Leaving out core intake details such as primary voltage, secondary voltage, and steady-state va.
  • Capturing values without checking whether they came from the actual installed equipment.
  • Sending the worksheet forward before anyone confirms the information is complete enough to act on.

Important note

Always confirm the exact nameplate data, drawing, primary and secondary values, burden, protection strategy, accuracy or inrush considerations, and environment, and manufacturer documentation before releasing a decision related to control transformer sizing.

FAQ

What belongs on this worksheet first?

Start with the field details that actually change the decision, such as primary voltage, secondary voltage, and steady-state VA.

Why not just send a quick email instead?

Because structured intake keeps the next person from making assumptions on missing nameplate, fit, or environment details.

Need help finding related parts?

Use the linked category or search path to compare available options against the ratings, fit checks, and application notes on this page.

Browse related parts

Technical Information Notice

The information in this article is provided for general educational and reference purposes. Industrial equipment selection, installation, and operation should always be verified against manufacturer documentation, applicable electrical codes, and the requirements of the specific application.

Strike Industrial does not design electrical systems and cannot evaluate every operating condition. Before installing or modifying industrial equipment, consult qualified personnel such as a licensed electrician, controls engineer, or equipment manufacturer when appropriate.