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Type: Posts; User: gar

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1. Thread: Help In Understanding Voltage Drop and Motors

by gar
Replies
2\$\$
Views
109

151007-2341 EDT JFletcher: You need a basic...

151007-2341 EDT

JFletcher:

You need a basic understanding of how various devices work, and then some analysis should help you understand how the devices can be used.

I will briefly touch on...
2. Thread: LED vs Incandescent in recessed fixtures

by gar
Replies
6\$\$
Views
295

151007-1017 EDT The materials in an...

151007-1017 EDT

The materials in an incandescent bulb can tolerate relatively high temperatures without failure. A small amount of the power input to an incandescent is radiated as visible light,...
3. Thread: LED lamps glowing

by gar
Replies
15\$\$
Views
645

151004-2128 EDT A simple experiment, or a...

151004-2128 EDT

A simple experiment, or a calculation will show that you can get a relatively large voltage reading from only a small amount of capactive coupling.

Experimentally use a variable...
4. Thread: LED lamps glowing

by gar
Replies
15\$\$
Views
645

151004-1435 EDT JohnJ0906: Have you...

151004-1435 EDT

JohnJ0906:

Have you determined the cause of your problem, and/or found a solution?

.
5. Thread: Industrial Apprentice here

by gar
Replies
3\$\$
Views
264

151002-0812 EDT Arguyle: At what Chrysler...

151002-0812 EDT

Arguyle:

At what Chrysler plant do you work?

The answer to your question is YES.

If you consider a perfectly staight conductor of electric current with no magnetic...
6. Thread: Short circuit withstanding of bus bars

by gar
Replies
15\$\$
Views
542

151001-1154 EDT LMAO: I believe you are...

151001-1154 EDT

LMAO:

I believe you are asking how to determine the force between two parallel conductors with equal currents, but in opposite directions.

Study a book such as "Electric and...
7. Thread: LED lamps glowing

by gar
Replies
15\$\$
Views
645

150939-2048 EDT Your illumination is not from...

150939-2048 EDT

Your illumination is not from some form of capacitance coupling unless the capacitor is large.

Experiment on two bulbs, one a Cree 120 V 9.5 W, the other unknown 120 V 9.99 W.
...
8. Thread: proximity switches wiring

by gar
Replies
10\$\$
Views
438

150939-0814 EDT petersonra: You did not...

150939-0814 EDT

petersonra:

You did not understand what I said. RTL and TTL are not specific to a particular voltage level, rather they are an output circuit concepts.

RTL has a pull-up...
9. Thread: Did your city ever have DC?

by gar
Replies
38\$\$
Views
1,167

150929-2346 EDT Following is photograph of a...

150929-2346 EDT

Following is photograph of a replica of the dynamometer (tangential force gage) used by Edison in 1879 to study the characteristics of his Dynamo. This is a good study in statics...
10. Thread: Did your city ever have DC?

by gar
Replies
38\$\$
Views
1,167

150929-2224 EDT The photograph in post #10...

150929-2224 EDT

The photograph in post #10 shows the type of dynamo used in 1879 at Menlo Park, and the same type was used on the Columbia. This was about a 5 kW unit with about 96% efficiency...
11. Thread: Single-phase generators supplying three-phase systems

by gar
Replies
21\$\$
Views
843

150929-2208 EDT If I understand the question...

150929-2208 EDT

If I understand the question correctly, then the three phase source connected to the panel is a wye source. Also there are no loads requiring three phase power, in particular three...
12. Thread: proximity switches wiring

by gar
Replies
10\$\$
Views
438

150929-1517 EDT If the prox switch has an RTL...

150929-1517 EDT

If the prox switch has an RTL (Resistor Transistor Logic) type of output, then it is much more sensitive to noise in the high state than if it has a TTL output (Tranaistor...
13. Thread: Did your city ever have DC?

by gar
Replies
38\$\$
Views
1,167

150928-2000 EDT Detroit had DC power. "1886...

150928-2000 EDT

Detroit had DC power.

"1886 The Edison Illuminating Company of Detroit was established and served its first customers. Seven years later, Edison Illuminating and other electric...
14. Thread: 240 feeding 208 volt motors

by gar
Replies
48\$\$
Views
1,679

150928-0758 ActionDave: I have been...

150928-0758

ActionDave:

I have been thinking about what you said about current increasing with applied voltage.

In the data I showed above the power input current for the unloaded motor...
15. Thread: 240 feeding 208 volt motors

by gar
Replies
48\$\$
Views
1,679

150925-1635 EDT ActionDave: If the motor...

150925-1635 EDT

ActionDave:

If the motor was mechanically fully loaded, then as voltage is changed the power input would be close to constant because the mechanical load is constant, but...
16. Thread: 240 feeding 208 volt motors

by gar
Replies
48\$\$
Views
1,679

150925-1610 EDT GoldDigger: I looked at the...

150925-1610 EDT

GoldDigger:

I looked at the current waveform, and I did not see a noticable indicator of saturation. The load is highly inductive, as we know it should be, under light load...
17. Thread: 240 feeding 208 volt motors

by gar
Replies
48\$\$
Views
1,679

150926-1132 EDT For comparison the...

150926-1132 EDT

For comparison the measurements on a 115 V 60 Hz 1/3 HP 1725 RPM single phase split phase motor with no mechanical load except bearings and windage are:

V In Amp ...
18. Thread: 240 feeding 208 volt motors

by gar
Replies
48\$\$
Views
1,679

150925-1349 EDT Attached is a graph of speed...

150925-1349 EDT

Attached is a graph of speed vs torque for a wound-rotor induction motor with rotor resistance being a parameter. From "Alternating-Current Machinery", Bailey and Gault,...
19. Thread: 240 feeding 208 volt motors

by gar
Replies
48\$\$
Views
1,679

150925-0955 EDT Various comments, I have not...

150925-0955 EDT

Various comments, I have not read all the posts, but I consider some as being incorrect.

Probably not mentioned in this thread, but Ohm's law does not include the power...
20. Thread: Cycle test noise ? Impulse test stand

by gar
Replies
1\$\$
Views
218

150924-0751 EDT I might be able to help, but I...

150924-0751 EDT

I might be able to help, but I have no idea what you are talking about.

In all probability a ground rod will be of no use at either or both test stands.

You have two test...
21. Thread: 50kva saturable reactor for globar hi-temp heat treat furnace

by gar
Replies
3\$\$
Views
252

150923-0652 EDT GoldDigger: I see too many...

150923-0652 EDT

GoldDigger:

I see too many questions ask on this forum where the questioner has done little research on their own before asking a question here.

How do you know whether...
22. Thread: LED bulb construction. Comparing types of bulbs.

by gar
Replies
8\$\$
Views
356

150923-0636 EDT Intensity vs voltage is driver...

150923-0636 EDT

Intensity vs voltage is driver dependent and a function of both input voltage and input waveform.

I ran some tests on different bulbs several years ago. The results are shown at...
23. Thread: 50kva saturable reactor for globar hi-temp heat treat furnace

by gar
Replies
3\$\$
Views
252

150922-2143 EDT TonopahJoe: A saturable...

150922-2143 EDT

TonopahJoe:

A saturable reactor has a finite impedance when the control signal is zero. Thus, you can not throttle your load current to zero.

For a useful discussion see...
24. Thread: 5% Single Phase Capacity on Center Tapped Delta Transformer secondary

by gar
Replies
7\$\$
Views
397

150922-1622 EDT mull982: When you use...

150922-1622 EDT

mull982:

When you use single phase transformers in a three phase system to provide a three phase output you can use any kind of transformer that will work. You could use an...
25. Thread: 5% Single Phase Capacity on Center Tapped Delta Transformer secondary

by gar
Replies
7\$\$
Views
397

150922-1204 EDT mull982: Consider an open...

150922-1204 EDT

mull982:

Consider an open delta and size the two transformers as needed. Or consider a closed delta with three transformers sized as needed.

.
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