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Search: Posts Made By: jraef
Forum: LIVE PLC Questions And Answers June 13th, 2019, 02:21 PM
Replies: 28
Views: 1,435
Posted By jraef
For a while I worked for Siemens Industry and we...

For a while I worked for Siemens Industry and we "rented" office space from Siemens Building Technologies, their BMS group. I didn't work with them much, but in sharing the work space and being the...
Forum: LIVE PLC Questions And Answers June 11th, 2019, 07:10 PM
Replies: 16
Views: 1,089
Posted By jraef
But with no nameplate, you don't know the number...

But with no nameplate, you don't know the number of poles...


If you knew what to look for in a stator, you could disassemble the motor and dissect the coils to see how many poles it has per...
Forum: LIVE PLC Questions And Answers June 10th, 2019, 03:44 PM
Replies: 12
Views: 722
Posted By jraef
I've been through this exercise before. The...

I've been through this exercise before. The Micro800 line is rated for up to 55C ambient (131F) and down to 0C (+32F), as are manyt of the standard "smart relay" products. The only one I know of...
Forum: LIVE PLC Questions And Answers June 7th, 2019, 01:18 PM
Replies: 27
Views: 1,473
Posted By jraef
They are, in my opinion, actually slightly better...

They are, in my opinion, actually slightly better than doing it with contactors in that there is no torque surge when banged on with a contactor, so the valve lasts longer and there are no contacts...
Forum: LIVE PLC Questions And Answers June 7th, 2019, 01:14 PM
Replies: 6
Views: 576
Posted By jraef
Also note that the first value, SC rating = 5kA,...

Also note that the first value, SC rating = 5kA, is per UL rules.
The "Short circuit current (co-ordination type 2)" is an IEC rating, and it is only in series with fuses, specifically type g or G. ...
Forum: LIVE PLC Questions And Answers June 7th, 2019, 09:24 AM
Replies: 2
Views: 274
Posted By jraef
Define what you mean by "open loop". Brake Slip...

Define what you mean by "open loop". Brake Slip Errors would only happen if you are using Flux Vector Control and Torque Prove in a lifting / hoisting application, it is looking at the encoder for...
Forum: LIVE PLC Questions And Answers June 6th, 2019, 05:19 PM
Replies: 16
Views: 656
Posted By jraef
Do what you want with contactor controlled...

Do what you want with contactor controlled motors, but +1 on the VFD controlled motors being terminated directly to the VFD terminals, ESPECIALLY the ground wires and shields (if any). You don't want...
Forum: LIVE PLC Questions And Answers June 5th, 2019, 04:55 PM
Replies: 27
Views: 1,473
Posted By jraef
What you are describing doing is, in the worst...

What you are describing doing is, in the worst case, to create a servo positioning control using a VFD. That is not as easy as it sounds with a feedback loop consisting of a pot like that. Most...
Forum: LIVE PLC Questions And Answers June 5th, 2019, 04:16 PM
Replies: 3
Views: 310
Posted By jraef
Think of it this way; Where is the power for...

Think of it this way;
Where is the power for the primary of that transformer coming from? basically if it is coming FROM the line terminals in your panel, it is ALREADY covered in the SCCR calc you...
Forum: LIVE PLC Questions And Answers June 2nd, 2019, 09:43 AM
Replies: 7
Views: 489
Posted By jraef
It’s done all the time, often called “load...

It’s done all the time, often called “load shedding”. The trickier part of this is not the PLC permissive interlock, it’s the sensing of when to make that decision. You/they will want a Load Monitor...
Forum: LIVE PLC Questions And Answers May 31st, 2019, 09:09 AM
Replies: 16
Views: 991
Posted By jraef
Good point and I should have brought that up....

Good point and I should have brought that up. Even if you use steel conduit, I now recommend using XHHW conductors, not THHN or THWN (on the OUTPUT side, input side doesn’t matter). You want Cross...
Forum: LIVE PLC Questions And Answers May 30th, 2019, 08:57 PM
Replies: 16
Views: 991
Posted By jraef
IMHO and experience you do not need shielded...

IMHO and experience you do not need shielded cable IF you use STEEL conduit and rigorously ground it (use grounding bushings, etc. etc.) and you use ONE CONDUIT RUN FOR ONE MOTOR (i.e. don't run the...
Forum: LIVE PLC Questions And Answers May 29th, 2019, 04:09 PM
Replies: 3
Views: 491
Posted By jraef
There was a small company in Napa CA called...

There was a small company in Napa CA called Control Manufacturing Co. (CMC) that was a System Integrator and control panel builder; that looks like their old logo. That's probably some sort of custom...
Forum: LIVE PLC Questions And Answers May 28th, 2019, 03:11 PM
Replies: 8
Views: 470
Posted By jraef
NFPA 79 only applies to controls for "industrial...

NFPA 79 only applies to controls for "industrial machinery" as defined in its own standard under section 3.3.55. It is NOT the same as the NEC and is only applicable if the AJH SAYS it is applicable,...
Forum: LIVE PLC Questions And Answers May 26th, 2019, 08:53 AM
Replies: 19
Views: 1,053
Posted By jraef
Because motor FLA is also used inside of the...

Because motor FLA is also used inside of the drive to set other things such as the equivalent circuit for vector control, jam protection, under load trip and the Short Circuit tripping...
Forum: LIVE PLC Questions And Answers May 26th, 2019, 08:46 AM
Replies: 2
Views: 369
Posted By jraef
“Weight Control using Vibrofeeder”... ...

“Weight Control using Vibrofeeder”...

Strapping a vibrator to your fork or spoon so that most of your food falls on the floor?

Sorry, couldn’t resist... :o:
Forum: LIVE PLC Questions And Answers May 24th, 2019, 02:47 PM
Replies: 13
Views: 925
Posted By jraef
What is your need for the brake? The reason I ask...

What is your need for the brake? The reason I ask is because if you use a worm drive gear motor package, the mechanical brake as a holding brake may be unnecessary and if you just want to stop it...
Forum: LIVE PLC Questions And Answers May 24th, 2019, 01:00 PM
Replies: 19
Views: 1,053
Posted By jraef
Sorry for the duplicated post, something is wrong...

Sorry for the duplicated post, something is wrong with my edit function.
Forum: LIVE PLC Questions And Answers May 24th, 2019, 12:58 PM
Replies: 19
Views: 1,053
Posted By jraef
Where people get that notion is actually the poor...

Where people get that notion is actually the poor way the NEC is worded and a lack of basic understanding of the concepts, coupled with people (mostly us guys) being unwilling to RTFM.


NEC...
Forum: LIVE PLC Questions And Answers May 24th, 2019, 12:56 PM
Replies: 19
Views: 1,053
Posted By jraef
Where people get that notion is actually the poor...

Where people get that notion is actually the poor way the NEC is worded and a lack of basic understanding of the concepts, coupled with people (mostly us guys) being unwilling to RTFM.


NEC...
Forum: LIVE PLC Questions And Answers May 24th, 2019, 12:36 AM
Replies: 19
Views: 1,053
Posted By jraef
The 125% pick-up point for overloads is 1) only...

The 125% pick-up point for overloads is 1) only in reference to motor with a 1.15 SF and 2) is baked into the algorithm (as it is with every solid state OL I have ever seen). Motor mfrs will tell you...
Forum: LIVE PLC Questions And Answers May 22nd, 2019, 11:12 PM
Replies: 2
Views: 301
Posted By jraef
You can get an F4 DC bus undervoltage when you...

You can get an F4 DC bus undervoltage when you have a lost or intermittent incoming phase, because the DC bus ripple becomes excessive for the load on the drive. It can also be an early indicator...
Forum: LIVE PLC Questions And Answers May 22nd, 2019, 11:09 PM
Replies: 12
Views: 617
Posted By jraef
If you use the NEC tables and rules to size the...

If you use the NEC tables and rules to size the conductors based on HP, you are covered for the 1.15SF, but there is a note about "unusual conditions" at the bottom that would apply to 1.25 SF or...
Forum: LIVE PLC Questions And Answers May 21st, 2019, 05:43 PM
Replies: 12
Views: 617
Posted By jraef
Not entirely true in North America though, at...

Not entirely true in North America though, at least from a code compliance standpoint...

The correct wire size is selected using a table in the NEC (similar in the CEC) that is based upon the...
Forum: LIVE PLC Questions And Answers May 21st, 2019, 05:33 PM
Replies: 18
Views: 1,200
Posted By jraef
Units bought on the "grey market" are either...

Units bought on the "grey market" are either surplus stock from some company's storeroom bought at an auction, used, or sometimes defective product that was supposed to be destroyed, but was...
Showing results 1 to 25 of 500

 
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