MTH Z4000 max power draw from the socket

I think the Z4000 is 400 watts, a "rough" calculation would be

15 amp circuit @ 120 volts = 1800 watts or approx. 4.5 Z4000's

20 amp circuit @ 120 volts = 2400 watts or approx. 6 Z4000's

if circuits are used only for Z4000's that would be the most possible

in a perfect setup (actual would be a bit less). Anything else on the

circuit would reduce those numbers.  So you shouldn't have any

problem with running 2 - Z4000's on either circuit.

Two of them would draw around 6 amps if fully used. Most outlets are 20 amps,some old house have some 15 amp sockets. Should be OK unless a lot of heavy appliances are on the same circuit. Good idea to plug these transformers into a surge suppressor on the outlet.

Dale H

A couple of years ago I did some load testing on  Z-4000.

I recall that when loaded up to the max output rating of 400 watts, the input load was 550 watts.

So you could in theory run three at max load, drawing 1650 total watts on one 15 amp 120 volt house circuit. Some more powerful handheld hair dryers are rated at 1750 watts, just as a comparison. 

Rod

The Z4000 I had, when fully loaded (which was rare) would register just under 4.5 amps at 122 volts on the outlet when I metered it.  That comes to 547 volt-amps and assuming 100% power factor that would mean just under 550 watts. 

Since only about 400 watts is going to the track, the 150 W difference ends up as waste heat, and that makes it clear why cooling fans exist. 

Did not think it was that inefficient.

Dake H

Thanks to all.  Great forum!

Gene

Most outlets are 20 amps,some old house have some 15 amp sockets.

Dale. when wiring a house, I always use 20-amp (12-gauge) for receptacles and 15-amp (14-gauge) for lighting circuits.  For what it's worth, a friend did mention to me that one reason is why builders generally install 14-gauge wire for receptacles outside the kitchen is that occupants plug lamps into them, which often have 18-gauge wiring and the 20-amp circuit doesn't provide adequate protection--neither does the 15 amp but the protection is slightly better.

I run 1 Z4000, 2 pw ZWs, and two TIU wall warts on a single 20-amp circuit.

I think the design of it and the ZW-L (which I have not tested at anywhere near its full 600+ watt output) are optimized for efficiency at far lower power outputs - those much more common and that near its maximum its not so efficient. I do know from feeling it that a lot of heat is given off at full output. 

I wonder what is the wattage of the blower.

RJR;

Do you mean the fan itself?

The Z-4000 uses a small computer style fan that would only consume a few watts of power.

I recall on my testing of the Z-4000 the air temp rise at full load settled at 27 deg F above room ambient. So the fan cooling system was definitely working.

Rod

Thanks, Rod.  Somehow the Lee Willis figures noted above indicate an efficiency much lower than I would expect from a modern transformer (not just a model train transformer)

I doubt the fan consumes enough power to really matter.  My experience with the design of transformers both wound and electronic (considerable) and consumer products (limited) is that engineers spend their employer's product budgets on adding those features or deleting those characteristics that matter in the selling of those products to the customers.  I've seen no evidence that efficiency matters at all i selling model train power supplies so I think no one made any effort: don't make it a design characteristic and usually that means its pretty bad by the time the product gets to the street (think of fuel economy of cars back when HP was important but MPG wasn't). 

Since I have several small power supplies (as for example to recharge my digital camera, the 18V batteries for my Black and Decker tools) that are around 50% efficient (they waste as much power as they net out), and one big product (my Chevy Volt, at 85% efficiency, "wasting" nearly 1.5 kWhr with each full recharge), I was actually surprised that the Z4K's efficiency was as high as it was.

Remember these have an electronic control that is also going to extra trouble to generate a pure sine wave.  This affects the efficiency over the simpler chopped sine wave units.