Recent Posts

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21
Our Shop / Re: The is a rotary phase converter question
« Last post by Alphawolf45 on February 15, 2019, 06:21:33 AM »
I got the idea for two rotary phase converters from the suggestion of a major rotary phase converter manufacturers website..
    I wouldn't like using a 40hp rotary phase converter every time I wanted to use the edm . The diesel or propane generator idea has real merit for running the injection molding machine.. I've seen decent old biguns for 3 or 4 thousand dollars.. 'Believe I'll start looking for one in another month after I have tests at the oncologist saying my cancer is indeed in remission. I have real 3 phase on a pole in my yard but would be a problem getting it into my shop because of big trees that would need to be taken down. And too, the cancer I had usually returns in 5 to 8 years so I don't need to be initiating another electric bill with cost of poles and transformers added in every month for who knows how long.
22
Our Shop / Re: The is a rotary phase converter question
« Last post by mc on February 15, 2019, 04:59:47 AM »
There will be, but on two identical RPCs they shouldn't be that different. Once you get over the initial connection, in reality there should be no difference between two RPCs running in parallel, and adding in an extra motor and capacitors.
23
Our Shop / Re: The is a rotary phase converter question
« Last post by awemawson on February 15, 2019, 02:55:07 AM »
You will get large circulating currents between the RPCs as the voltages when open circuit will never be the same.
24
Project Logs / Re: Miniature coil winder
« Last post by awemawson on February 15, 2019, 02:52:00 AM »
Well done Doc.

(Though I'd be nervous of using plywood as the insulator at that sort of voltage)
25
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by cnc-it on February 14, 2019, 11:06:44 PM »
It looks like the servo is overshooting?..I've had this on the older Siemens dC drives..it looked just like this symptom. I increased the gain with the proportional gain pot until it settled down.

If I'm correct it's pot R125 (x axis) , R225 (Yaxis) , R325 (ZAxis)  Kp (n) on the AC drives. The manual says turn the gain up if you have inaccurate positioning.



 

 
26
Tools / Re: Did I Overdo the Files ?
« Last post by WeldingRod on February 14, 2019, 10:11:40 PM »
Mcmaster has lathe files, and I can confirm they work ;-)

Sent from my SAMSUNG-SM-G891A using Tapatalk

27
Project Logs / Re: Miniature coil winder
« Last post by Doc on February 14, 2019, 08:07:20 PM »
Here are some pics of the finished coil. It puts out a nice spark at 6V. The primary resistance is 3.0 ohm and the secondary is at 5600 ohms. I'm happy with the way it turned out one more thing I can cross off my would like to build if I could.
28
Our Shop / Re: The is a rotary phase converter question
« Last post by mc on February 14, 2019, 06:36:45 PM »
Paralleling two RPCs could be done.  Ensure phases are matched, run both up to speed, then connect them together.
The input frequency takes care of ensuring speeds match, you'd just need to ensure the correct phases are matched.

If you're unsure, I'd wire in some relatively low value fuses (5A would probably be good enough for testing) the first time you try connecting both, as I'd rather blow some small fuses if phases are mismatched, than rely on the main breaker.
29
How do I?? / Re: LED lamp. With PIR switching......
« Last post by Stilldrillin on February 14, 2019, 05:16:23 PM »
Problem solved!  :thumbup:

I thought, I already had a spare PIR. High up, on the top of the workshop cupboard.....
 Unfortunately, I've recently had a new roof installed. The shop area is a complete and total TIP.
After a thorough search. I ordered one from ebay. £5.99. 

The following morning. It was on the front of the workbench, in plain view!! Obviously, put there overnight by the shop gnome.....  :bang:

According to the receipt, I paid £8.99 for it. In 2004......

I'm pleased to say. The 15yr old, new switch, is working perfectly......  :thumbup:


And..... I still have a spare......  :palm:
30
Our Shop / Re: The is a rotary phase converter question
« Last post by vintageandclassicrepairs on February 14, 2019, 03:38:17 PM »
Hi Alpha,
Not knowing whether you live in an urban or rural location may render my suggestion useless ??
The price of two 20hp RPC's is not to be sneezed at !!!
Would a diesel generator be an alternative ? if it is not to be run full time it should be economical enough.
They come up secondhand regularly

I do not think its very feasible to parallel 2 RPC's
Unless you could split the electrical load between them ?

John
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