Recent content by CruiserFJ62

I have an enclosure in which the electrical components put off 10,500BTU/hr. At the top of the enclosure the internal hot air is in contact with circular aluminum tubes. Ambient outside air at 70 degrees F is blown through the center of the tubes at 500cfm. Internal hot air and outside ambient...

I am in the process of designing a grounding assembly for a high voltage switch and need to determine what contacts will handle 1200amps. The contacts are U-shaped and a flat copper conductor bar rotates into the U-shaped contact to make the connection. Can anyone point me to a reference or give...

I am working on a project in which I need to know how high voltage arcing occurs. Will arc travel the line of sight path or will it take the shortest distance which has the 90degree angle? What is the reasoning behind the path that it chooses and does anyone have any websites or articles that...

I have a heat source inside a steel box. I know the outside ambient air temp and the amount of heat the source puts of. How do I calculate the internal air temp of the box?

What are the effects when the nut is welded to a structure and the bolt is threaded into the welded nut?

I'm not really trying to get an exact answer but an understanding of what the worst case would be if the material was in its annealed state?

Does anyone know of a table shows annealed vs tempered&quenched steel properties? What is the decrease in yeild stress on a grade 8 bolt that is annealed due to the heat from welding?

What are the effects when welding takes place on a fastener. If the head of a bolt or nut is welded to a plate how does it change the properties of the hardware?

Yes, what is the temp inside the enclosure? I am trying to determine if the natural convection through the louvers can pull enough heat out to keep the transformer below its rated operating temp. Any ideas?

I have a transformer in a box that is cooled using natural convection. There are louvered openings on the box to pull cool air in the bottom and let heated air out of the top. How do I determine how much heat is actually leaving the enclosure? Info that I have is the area of the enclosure, the...

Can anyone point me to so tabulated friction coefficients for rolling resistance both when moving and from a stopped position? I'd like to see the varience between the two.

Would the value calculated for rolling friction be the force to keep it moving at a constant velocity? What about the force required to start the wheels rolling. Is there a higher friction value to use from the stationary position? Similar to static and kinetic sliding friction?

I think you have enlightened me. So if the four wheels were locked up and sliding on the steel deck I would use the coef of sliding friction .74. But since they ideally won't be sliding I would use the rolling resistance.

That is the equation that I was using, but i was using the static coeff for steel on steel of .74. What are the coeff that you listed above?

Ok, so overcoming friction is going to be the max required force. What equation would you use to determine this? Neglecting bearing friction for the time being and only dealing with the friction between the wheels and the ground what equation would you use to determine the force required to get...