ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
Potseal 11
sparky 5
Recent Posts
Permit Snafus...AHJs and Contractors Jump in
by HotLine1. 04/30/17 02:30 PM
201 volt equipment?
by bigpapa. 04/29/17 12:15 AM
Schneider LC1D09
by jraef. 04/28/17 11:05 PM
Electrode boilers question
by annemarie1. 04/27/17 01:40 PM
Why cables look like they do
by LongRunner. 04/26/17 09:36 AM
New in the Gallery:
SE cable question
Popular Topics(Views)
235,042 Are you busy
169,884 Re: Forum
163,072 Need opinion
Who's Online Now
0 registered members (), 34 guests, and 9 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#138634 - 09/19/03 08:12 AM Power in space station  
C-H  Offline
Member
Joined: Sep 2002
Posts: 1,497
Stockholm, Sweden
From Boeing:

Rocketdyne is responsible for the end-to-end electrical power system for the International Space Station.

The system consists of power generation, energy storage and power management and distribution. The system provides 78 kw to the users with the power being generated by four photovoltaic (PV) Array Modules. Each module consists of two flexible deployable array wings of silicon solar cells supported by an extendible mast.

The station orbits the earth every 95 min. spending approximately 2/3 of the time in sunlight 1/3 in eclipse. Power is provided during sunlight by the PV Arrays. During the eclipse the 78 kw of station power is provided by Nickel-Hydrogen batteries which are charged during the sunlit part of the orbit.

The power management and distribution subsystem distributes the power at 160 volts DC around the station through a series of continuous duty, DC contactor switchgear. The switchgear has built-in microprocessors, controlled by Ada software and connected to a data bus running throughout the station. DC-DC converter units stepdown and condition the voltage from 160 to 120 volts DC to form a secondary power system to service the loads through solid-state switchgear. The converters also provide isolation of the secondary from the primary system and maintain uniform power quality throughout the station.


Test Equipment:
Large Selection of Test Equipment For Electrical, HVAC, Test & Measurement
Large Selection of Test Equipment For Electrical, HVAC, Test & Measurement

#138635 - 09/19/03 07:17 PM Re: Power in space station  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Wow, that's quite a continuous load to supply from PV panels, although they have the advanatge of not having to worry about cloudy days! [Linked Image]

It would be interesting to know the reasons behind the decision to use 160V as the level for primary distribution.


#138636 - 09/19/03 09:01 PM Re: Power in space station  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
The 120VDC choice is interesting.

48VDC {24-cell battery set} is common in a lot of communications, with some 48- and a lot of 125VDC {60-cell battery string} use in electrical transmission and distribution for breaker tripping and other critical loads where there is a chance of AC-power nonavailability. That way everything can crash and burn outside [or otherwise not be 110% reliable] the switchyard breakers can still be operated. Arcing burndowns are bad enough on 480Y systems—it can be phenomenally worse at higher voltages.


#138637 - 09/19/03 09:21 PM Re: Power in space station  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
Minor aside — On spacecraft voltage changes, such an oversight is what led to the Apollo 13 disaster. There were heaters for cryogenic oxygen tanks, with a simple thermostat control cycling the heaters to boil off gaseous oxygen to keep the crew breathing.

Over various stages of spacecraft development, the heater voltage {and battery set} went from 28 to 65VDC. [This might be roughly comparable to using a 250V fusible switch called on to interrupt a 600V motor circuit.] Unfortunately, the thermostat contact spacing remained at the 28V spec, passing all design testing but, while sensing contents temperature on the tank wall 250,000 miles away it failed catastrophically, rupturing the tank.


[This message has been edited by Bjarney (edited 09-19-2003).]


#138638 - 09/19/03 09:22 PM Re: Power in space station  
SvenNYC  Offline
Member
Joined: Aug 2002
Posts: 1,691
New York City
So what voltage do I have to set my radio cassette player before plugging it in? [Linked Image]

Or do I have to dig out one of my DC radios?


#138639 - 09/20/03 04:05 PM Re: Power in space station  
classicsat  Offline
Member
Joined: Nov 2002
Posts: 456
They would supply the necessary switching DC-DC convertor, or a supply of rechargeable packs, charged by a DC charger. The laptop computers, since they probably have universal switcher supplies, witll most likely operate fine off of the DC power system. The lights also would have SS ballasts.


#138640 - 09/20/03 08:59 PM Re: Power in space station  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,211
SI,New Zealand
C-H,
Thanks for that!, [Linked Image]
I've always wondered what sort of Electrical system that they used up there.
We get the odd Comms coming through on our 2-metre Ham band over here, it's good to hear them, but it's all in Russian!
That would look real good on the CV, "performed Electrical wiring out in Space!" [Linked Image]


Let's face it, these days if you're not young, you're old - Red Green grin

#138641 - 09/21/03 12:49 PM Re: Power in space station  
C-H  Offline
Member
Joined: Sep 2002
Posts: 1,497
Stockholm, Sweden
A service call might be a bit tricky, though. [Linked Image]


#138642 - 09/22/03 07:31 PM Re: Power in space station  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
And at the cost per mile travel they'd have to charge, the words you don't want to hear are "We don't carry them in the spaceship. We'll have to pop back to Earth to get one!" [Linked Image]



Member Spotlight
dougwells
dougwells
kamloops BC Canada
Posts: 1,137
Joined: May 2003
Show All Member Profiles 
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.017s Queries: 14 (0.004s) Memory: 0.8029 MB (Peak: 0.9702 MB) Zlib enabled. Server Time: 2017-05-01 00:16:53 UTC