Recent content by Futsal1st

Sorry 'bout that. Its a car park roller door that has small openings (almost rectangular)about 5mm high and 50mm long. It acts like a perforated panel between the outdoor and the car park.

Its a louvred roller door.

How do I determine the pressure drop of air across an opening? For example if I have 3,000 L/s (3 m3/s) and an opening of 8.4 m2 I know the velocity is 0.4 m/s. If the free area is 80%, the velocity increases to 0.45 m/s. What I'd like to cal is the pressure drop in each case. Cheers

a piece of toilet tissue is held against a ceiling grille. Is it held there by air velocity or differential pressure. If the grille exhausting 50l/s through a 100x100mm egg crate opening the tissue may be held up. If however the same air flow gives through a 500x500 mm grille, it will fall...

I am looking at a building with a car park in Sydney. Electrical circuits are run on perforated cable trays at high level. I understand that the trays require earthing, however, I'm trying to determine the extent. The trays are made from galvanized sheet and come in 3 meter lengths and are...

So is thermal conductivity divide by a unit depth (I assume 1000mm) and multiply by area = U factor?

So is it divide by a unit depth (I assume 1000mm) and multiply by area?

Thanks for that. So is thermal conductivity multipied by the area of the surface the U Factor (or close as damn to it)?

I understand that thermal conductivity is W/(m.K) and u-factor is W/m² K. Obviously U factor is energy transfer over an area but how does this compare to thermal conductivity?

Thanks for the reply.

I understand that Dielectric Strength relates to the point where a compound breaks down under electrical load. Please correct me if I have it wrong. I want to now if an RTV compound (with Dielectric Strength of approx 500 volts/mm) is safe to use across 240v or 415v terminals that are 3-5mm...

Thanks for that. He owes me a beer.

Thanks for the input. The type of generators are the portable ones. Each generator has a power outlet (GPO) to connect the extension lead. He was thinking of making up a cable, via a junction box to power the plant (like a 'Y' extension lead) from two generators. This would mean that you...

I have a question in relation to electrical generators, 240VAC 50 Hz. A colleague wants to run a piece of gear that draws around 10A @ 240VAC with a pf of 0.8. He has indicated that running two 2kVA generators in parallel will provide greater ampage output, thus allowing the equipment with power...