Loadmeter question

[sgreen91 182]

With either GPU or APU should you not see voltage and frequency on the L and R selectors of the load meter?  I watched a video CBT on the MD80 on Youtube and it showed with either external or internal power you should have voltage on the left and right systems.

I noticed in the X-plane version of the MD80 they model this correctly which at first I thought they modeled incorrectly.

[thibodba57 462]

1 hour ago, sgreen91 said:

With either GPU or APU should you not see voltage and frequency on the L and R selectors of the load meter?  I watched a video CBT on the MD80 on Youtube and it showed with either external or internal power you should have voltage on the left and right systems.

I noticed in the X-plane version of the MD80 they model this correctly which at first I thought they modeled incorrectly.

You'll have to provide a link to this youtube video so I can see what where the confusion might be.  That doesn't sound right at all.  The subject line you are referencing the Loadmeter and in the post you are referencing Freqs and Volts.  Load and Freqs and Volts are not read on the same instrument.  Loadmeters refer to only the Generator as you can't have a 50% draw on a AC bus.  Either its powered or its not.  You also don't read Frequency or Volts on a AC Bus (DC you do).  AC Power is very clean and so long as Freqs and Volts are in limits from the power source the AC Bus is being properly powered.  You are more than welcome to try to look for a AC Bus Freq/Volt/Loadmeter on another 737 aircraft I ca think of, but you'll only find selectors refering to the AC Power sources. or DC Power.

[sgreen91 182]

 

 

[sgreen91 182]

1 hour ago, thibodba57 said:

You'll have to provide a link to this youtube video so I can see what where the confusion might be.  That doesn't sound right at all.  The subject line you are referencing the Loadmeter and in the post you are referencing Freqs and Volts.  Load and Freqs and Volts are not read on the same instrument.  Loadmeters refer to only the Generator as you can't have a 50% draw on a AC bus.  Either its powered or its not.  You also don't read Frequency or Volts on a AC Bus (DC you do).  AC Power is very clean and so long as Freqs and Volts are in limits from the power source the AC Bus is being properly powered.  You are more than welcome to try to look for a AC Bus Freq/Volt/Loadmeter on another 737 aircraft I ca think of, but you'll only find selectors refering to the AC Power sources. or DC Power.

Sorry for the confusion I was at work and not able to access the docs.  Its the AC and DC power indicators that I'm discussing.

[thibodba57 462]

3 minutes ago, sgreen91 said:

Sorry for the confusion I was at work and not able to access the docs.  Its the AC and DC power indicators that I'm discussing.

K, I'll still reference what I said before.  You don't monitor Freqs and Volts of a Bus only the supplying source.  AC power is either on or off.  If there is a short of some sort a Breaker will pop and then all there is todo is isolate the bus.  It doesn't really matter what the voltage is at that point.  But it is important to know what the Freqs and Volts of a supplying source is though.

I'll have to see the CBT to try to understand what they are trying to tell you. There might be some sort of confusion.

Edited March 1, 2018 by thibodba57

[sgreen91 182]

Ok gotcha.  I was just following the procedure in the video and it came up different in the simulated aircraft when he switched to the R.  Not a big deal.

[thibodba57 462]

No worries.  The selector there is to see the Power Source Freq Volt AND the DC Bus.  Maybe you misunderstood at that point.  I will say this plane is an oddity in that aspect.  The same selector will show the Volts of the DC Bus while its show the Freq/Volt of the AC Generator.  The DC indication is to the right of the selector.

[FormerSF3 15]

Go to 8:40 in the video and it shows an engine shut down.  You will see the VOLTS/FREQ drop to zero when selected to L/R.

The L/R voltage selectors do 2 things.  1. Show the VOLT/FREQ of the operating generator.  2.  Shows the respective side DC Bus Voltage.  On the ground with engines shut down you will only get the DC voltage.