What Size Rheostat for 110 VAC 400 W Drymount Press?

  • Thread starter Thread starter dbirley
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around selecting an appropriate rheostat for a 110 V AC, 400 W drymount press that lacks temperature control. Participants explore options for controlling the voltage to manage heat dissipation during extended use.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests building a control box with a rheostat to reduce voltage due to overheating concerns.
  • Another participant recommends using a rheostat rated for at least 1.5 times the wattage, suggesting a 600 W or even an 800 W rheostat for safety against heat issues.
  • A different participant questions whether the 400 W rating includes the heating elements, implying that a lower-rated rheostat might suffice if the heating elements are not fully utilized.
  • Some participants advocate for using a switched mode device, such as a lamp dimmer or motor speed controller, instead of a rheostat, citing that rheostats are outdated for power applications.
  • A later reply confirms the use of a dimmer switch with a 600 W capacity as a solution, detailing the setup process and expressing satisfaction with the outcome.

Areas of Agreement / Disagreement

Participants express differing views on the appropriateness of rheostats versus switched mode devices, with some advocating for traditional rheostats and others suggesting modern alternatives. There is no consensus on the best approach to voltage control for the drymount press.

Contextual Notes

Some assumptions about the heating elements' ratings and their contribution to the overall wattage are not clarified, which may affect the recommendations for rheostat sizing.

dbirley
Messages
2
Reaction score
0
I have a drymount press that runs on 110 V AC, and is rated at 400 W. It runs too hot and has no temperature control on it, so I need to build a simple control box with a rheostat in it to reduce the voltage reaching it. Not sure what size of rheo to look for. Typically the "work cycle" of the whole unit could run to an hour or more, so heat dissapation on the rheo will be a concern.

Any suggestions?
 
Engineering news on Phys.org
A good rule of thumb is to use a rheostat that is rated for at least 1.5 time the wattage that you are going to use. In this case that would be 110 V, 600 watt. But if heat is a big concern you could even use an 800 watt rheostat. It will be more expensive, but it will probably be worth it.
 
You mention the rated power of 400 watt. If this is for the heater plus the press, you might be able to get by with something less. Do you know the rating of the heating elements?
Welcome to PF.
 
You want a switched mode device like a lamp dimmer or motor speed controller. Rheostats haven't been used for power applications for decades.
 
Pumblechook said:
You want a switched mode device like a lamp dimmer or motor speed controller. Rheostats haven't been used for power applications for decades.

Yup -- I had a big "Doh" after starting the thread. A dimmer switch with a 600W capacity is the answer, and I rigged the whole thing up using a 10' extension cord with molded fittings, whacked off the receptical end and wired it into a 4x4x4 box with a standard recep and a nice faceplate. Life is beautiful -- thanks to everyone for the input!
 

Similar threads

  • · Replies 56 ·
2
Replies
56
Views
54K
  • · Replies 12 ·
Replies
12
Views
17K
Replies
5
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 10 ·
Replies
10
Views
9K
  • · Replies 287 ·
10
Replies
287
Views
27K
Replies
77
Views
24K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K