Search found 45 matches

by upsmaster
Sat Feb 25, 2006 7:09 am
Forum: General Discussion
Topic: running a vfd on single phase
Replies: 4
Views: 1114

Re: running a vfd on single phase

1 or 3 phase 1 phase can mean 240/220/208/277 phase to phase and not always phase to neutral. i think u can find a transformer 120 to 480 but not sure big enough to support 2 horsepower but a 220/240 to 480 would be a better way to go, just be sure what 1 phase is to the drive joe
by upsmaster
Wed Oct 26, 2005 1:49 pm
Forum: General Discussion
Topic: Isolated 12 VDC input to PLC
Replies: 5
Views: 1039

Re: Isolated 12 VDC input to PLC

A dc/dc converter with a 9 to 18 volt dc input with a regulated 5 volt out would work. These devices come in isolated fully ot not so isolated, price is mostly based on those features and wattage.

joe
by upsmaster
Wed Aug 31, 2005 6:06 pm
Forum: General Discussion
Topic: PWM motor circuit and diode
Replies: 31
Views: 5098

Re: PWM motor circuit and diode

try a fast recovery diode or increase the piv voltage rating.<p>
joe
by upsmaster
Mon Jun 27, 2005 2:13 pm
Forum: General Discussion
Topic: mystery connector?
Replies: 15
Views: 2720

Re: mystery connector?

its a high z mike connector for a high z mike useing coax wire standard on high z mikes..never though it would be hard to find.
joe
by upsmaster
Mon Jun 27, 2005 2:09 pm
Forum: General Discussion
Topic: Three phase power, from 220V line??
Replies: 7
Views: 2250

Re: Three phase power, from 220V line??

3phase is 208 line to line 120 line to neutral or 480 line to line 277 line to neutral 3 phase is 120 degrees apart phase to phase 240 single phase line to line 120 line to neutral the 2 lines are 180 degrees apart...so the panel maybe for 3 phase service but is wired for single phase 240 joe
by upsmaster
Tue Jun 21, 2005 2:08 pm
Forum: General Discussion
Topic: 24kw AC generator frequency problem
Replies: 25
Views: 4856

Re: 24kw AC generator frequency problem

most of the time the number of poles in a genrator determine how smooth the ouuput wave shape is... your gen shows a normal wave shape. i think that the notch that you see at the top and bottom of the sine wave is the excitation supply rectifier turning on at the reverseing of the sine wave as the s...
by upsmaster
Mon Jun 20, 2005 6:46 pm
Forum: General Discussion
Topic: 24kw AC generator frequency problem
Replies: 25
Views: 4856

Re: 24kw AC generator frequency problem

wave form looks better than i would expect. your scope shows each leg 180 degrees apart normal for 120 to neutral the zero crossing are the same for both legs showing that they are the same hz if they were 60/120 the zero crossings would not match joe
by upsmaster
Mon Jun 20, 2005 2:11 pm
Forum: General Discussion
Topic: 24kw AC generator frequency problem
Replies: 25
Views: 4856

Re: 24kw AC generator frequency problem

This is normal for a small AC generator just load it with some light bulbs, space heaters , and you will see the wave form smooth into a fairly nice sine wave... un loaded it will be very rough.. the more load the better...
joe
by upsmaster
Thu Jun 16, 2005 3:56 pm
Forum: General Discussion
Topic: Event Per Hour
Replies: 7
Views: 1573

Re: Event Per Hour

Hi
Maybe try Red Lion Controls they make a large selection of process meters I used them a lot for feet per min/sec and total feet. most meters have more than one type of input and some have outputs too..check them out.
joe
by upsmaster
Tue May 31, 2005 2:17 pm
Forum: General Discussion
Topic: Books on Op-Amps
Replies: 9
Views: 1407

Re: Books on Op-Amps

yes for your summer reading list Operational Amplifiers Design And Applications Burr-Brown Tobey-Graeme-Huelsman McGraw-Hill 1971 Designing With Operational Amplifiers Applications Alternatives Burr-Brown Graeme McGraw-Hill 1977 Handbook of Operational Amplifier Circuit Design Stout-Milton McGraw-Hi...
by upsmaster
Sat May 07, 2005 2:57 pm
Forum: General Discussion
Topic: How is power fed back into the grid?
Replies: 18
Views: 4496

Re: How is power fed back into the grid?

Well i'm not real sure but the inverter must be in sync with the line hz...most of the time this is done electronicly by leting the line hz control the inverter hz within a narrow window of cycles and i think that the voltage must be controled also if the inverter ac voltage is lower than the line t...
by upsmaster
Thu Apr 21, 2005 6:24 pm
Forum: General Discussion
Topic: Backup power for PLC
Replies: 5
Views: 1337

Re: Backup power for PLC

let the plc run on your battery all of the time. a ups uses a static switch to slect between com power or inverter power to the output to the load. not really fast switching just that both sides of the switch are on for one quarter cycle for no break when slecting one or the other source. joe
by upsmaster
Thu Apr 21, 2005 5:56 pm
Forum: General Discussion
Topic: Backup power for PLC
Replies: 5
Views: 1337

Re: Backup power for PLC

Maybe a dc to dc converter with a input range of
8 to 16 volts dc and 12 out, some plc have internal battery back up option but not sure how long they are designed to hold up for
joe
by upsmaster
Fri Mar 11, 2005 5:32 pm
Forum: General Discussion
Topic: Two Transformers
Replies: 12
Views: 1771

Re: Two Transformers

hi
as a rule D.C will not share the load equaly...you can try to force it... may not be easy..A.C. shares better.
joe
by upsmaster
Fri Feb 11, 2005 6:20 pm
Forum: General Discussion
Topic: auto amp
Replies: 14
Views: 2096

Re: auto amp

Hi 400 watts mostly peak ratings yes there is dc to dc converter in the power supply to raise the voltage to 40 or so volts. Any battery charger you use with a cap across the buss may not work because of cap charging inrush depends on cap charger amp combo and a dc/dc converter draws a large slug of...