Secondary voltage on transformer

Click For Summary

Discussion Overview

The discussion revolves around the secondary voltage output of a transformer with a primary voltage of 120V AC and a turns ratio of 5:1. Participants explore the implications of the turns ratio on voltage transformation and the conditions necessary for proper transformer operation.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant claims that with a 5:1 turns ratio, the secondary voltage should be 600V AC, but this is questioned by others.
  • Another participant seeks clarification on which winding has more turns, indicating uncertainty about the turns ratio's application.
  • A different participant suggests that if the primary has 5 times as many turns as the secondary, connecting 120V across the primary would yield 24V across the secondary.
  • Conversely, if the transformer is connected the other way, it could produce 600V across the primary, raising concerns about the transformer's design and safety.
  • Concerns are raised about the inductance of the winding with 120V across it, emphasizing the need for sufficient inductance to prevent excessive current that could damage the transformer.
  • A guideline is mentioned regarding the number of turns needed per volt for small transformers, suggesting that a simple 5:1 ratio may not suffice for a 120V application.

Areas of Agreement / Disagreement

Participants express differing views on the correct interpretation of the turns ratio and its implications for voltage output. There is no consensus on the correct secondary voltage or the conditions under which the transformer operates safely.

Contextual Notes

Participants highlight the importance of understanding the relationship between turns ratio and voltage, as well as the inductance requirements for transformer operation, but do not resolve the specific calculations or assumptions involved.

bwd111
Messages
6
Reaction score
0
120 v ac primary and turn ratio of 5:1 I came up with 600v ac is this wrong
 
Engineering news on Phys.org
Which is the 5 and which is the 1?
 
5:1 ratio on secondary 120v ac primary x5 /5 = 24v secondary
 
Sorry, I don't understand. Is your question answered? If so, great. If not, I still don't know whether the primary has 5X more turns than the secondary or vice-versa.
 
If you had a transformer which had two windings with a turns ratio of 5 times as many turns on one winding as the other, and you connected 120 volts across the larger winding, you could get 24 volts across the smaller winding.

If you connected them the other way around, you might get 600 volts.

A complication you need to know about is that the winding with 120 volts across it needs to have enough inductance to stop a large current flowing in that winding.
Otherwise, the transformer could be destroyed.
A rough guide for small transformers is that there should be about 5 turns of wire for each volt put across the winding.

So you can't just have 5 turns and 1 turn and have it work at 120 volts.
 
Last edited:

Similar threads

How to wind a 5K audio tube amplifier transformer?
  • · Replies 9 ·
Replies
9
Views
3K
Inducing Voltage in a Transformer: How Does It Work?
  • · Replies 3 ·
Replies
3
Views
2K
"Ground" and "Center Tapped" Power Transformer Secondary in guitar amp
  • · Replies 6 ·
Replies
6
Views
4K
Need help with a parallel inductance calculation for this transformer
  • · Replies 2 ·
Replies
2
Views
2K
How does back EMF contribute to the operation of an autotransformer?
  • · Replies 64 ·
3
Replies
64
Views
8K
Magnetics Question; is the Answer Really as Obious as it Might Seem?
  • · Replies 8 ·
Replies
8
Views
2K
Step down transformers used in residential AC Mains distribution
  • · Replies 2 ·
Replies
2
Views
1K
Partial Discharge Analysis for Transformer Insulation Testing
  • · Replies 1 ·
Replies
1
Views
1K
How might electronics be different if AC voltage was 72V at 45 Hz?
  • · Replies 30 ·
2
Replies
30
Views
3K
Maximum power from a transformer
  • · Replies 8 ·
Replies
8
Views
3K