Search found 45 matches

by upsmaster
Fri Feb 11, 2005 6:09 pm
Forum: General Discussion
Topic: looking for a voltage tester
Replies: 15
Views: 3180

Re: looking for a voltage tester

Hi
go to http://www.datel.com
Then click on Digital Panel Meters
Click on 2-Wire Mmeters at bottom of page click
on AC Voltmeters you might find what you want<p> joe
by upsmaster
Sun Feb 06, 2005 4:37 am
Forum: General Discussion
Topic: H bridge
Replies: 14
Views: 3791

Re: H bridge

Hi 4) Toshbia<p> 5) 8,000 Hz to about 30,000 Hz<p> 6) Toshbia...their is no easy way you must meet the device specs.<p> 3) Clamp a device across the gate of the igbt to keep the gate in an off state when no gate signal is present.<p> 2) Rectifier/DC power source.. the caps are across the dc bus.<p> ...
by upsmaster
Sat Feb 05, 2005 6:53 am
Forum: General Discussion
Topic: H bridge
Replies: 14
Views: 3791

Re: H bridge

Hi
oh yeah you must have a dead band between turning off one set of igbts and turning on the other in a h bridge, this is so the igbt is of our circuit has a 2.5 mircosecond dead band.<p> joe
by upsmaster
Sat Feb 05, 2005 6:50 am
Forum: General Discussion
Topic: H bridge
Replies: 14
Views: 3791

Re: H bridge

hi We keep a steady -15 volts on the gate when inversion is halted..also when we start a inverter we turn on a rectifier first, this gives us our electronics through a dc/dc converter supply which puts the -15 volts on the gate this keeps them off. The rectifier also charges up all of the dc caps in...
by upsmaster
Wed Feb 02, 2005 5:10 pm
Forum: General Discussion
Topic: H bridge
Replies: 14
Views: 3791

Re: H bridge

hi<p> some clues for you, we use igbt's in H bridges for dc to ac inverters. our inversion circuits are 48,120,240,360 volts dc input with single phase outputs at 120,120/240,208 and three phase 208,480 volts ac. ranges from 10 to 300 kva. manufactures spec books/data sheets will show a series resis...
by upsmaster
Sat Jan 22, 2005 4:26 am
Forum: General Discussion
Topic: Charging 12V Battery while riding Bicycle
Replies: 19
Views: 4816

Re: Charging 12V Battery while riding Bicycle

parallel two 6 volt batterys for charging then series them for 12 volts discharging<p> joe
by upsmaster
Sun Jan 16, 2005 6:07 am
Forum: General Discussion
Topic: PULSE HELP!
Replies: 9
Views: 2023

Re: PULSE HELP!

if i understand your spec. a control relay will trigger a circuit to delay the turn on of a second relay and after this delay and turn on of second relay is to latch on ... there are delay on activate relays off the shelf with fixed or adjustable time delays that latch <p> joe
by upsmaster
Sat Jan 15, 2005 1:46 pm
Forum: General Discussion
Topic: Questions about making circuit boards
Replies: 15
Views: 3727

Re: Questions about making circuit boards

the pretty green is a solder mask for wave soldered boards... maybe you can draw your logo and have a office supply make a stamp for you, then you can get any color of ink. you can conformal coat your boars with spray can technology after your finished but it covers everything and makes shooting tro...
by upsmaster
Sat Nov 27, 2004 11:25 am
Forum: General Discussion
Topic: Melting Point of Plexiglass?
Replies: 33
Views: 7606

Re: Melting Point of Plexiglass?

hi

Try www.mcmaster.com for raw just about anything u need. try aavidthermalloy.com for hearsink info and free software Cool-Cat down load this may help.<p> joe
by upsmaster
Wed Nov 17, 2004 1:26 pm
Forum: General Discussion
Topic: lead acid battery theory question
Replies: 5
Views: 1812

Re: lead acid battery theory question

checked out web site ..lots of misinformation and incomplete information

joe
by upsmaster
Tue Oct 05, 2004 10:53 am
Forum: General Discussion
Topic: Power inverter
Replies: 3
Views: 1120

Re: Power inverter

try www.ltipowersystems.com
and solid state inverters have les than 1% total harmonic distortion
joe
by upsmaster
Sun Aug 08, 2004 5:55 am
Forum: General Discussion
Topic: Stray 110 voltage
Replies: 16
Views: 4242

Re: Stray 110 voltage

my guess is their is no voltage. Digital meters give false readings when the circuit is open that they measure across. try a analog meter. and adding a resistor at that point will make the circuit complete and the 5 volt reading will go away.<p> joe
by upsmaster
Sat Jul 17, 2004 7:51 am
Forum: General Discussion
Topic: Oscilloscope Setup
Replies: 6
Views: 1593

Re: Oscilloscope Setup

I think u don't need the second scope ground clip the clip is common to both probes and the earth ground and the scope cabinet. If u have a ground lift then u are isolated from the earth ground and if u need to use both ground clips then in most cases ur inputs on the scope are isolated. We have use...