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Type: Posts; User: gar

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1. ## Thread: Same HP at Lower RPM?

by gar
Replies
8\$\$
Views
148

### 150417-1001 EDT rhenders: You should have...

150417-1001 EDT

rhenders:

You should have been able to answer that question yourself, but is there more to the real question.

Depending upon on the motor characteristics you might be able to...
2. ## Thread: 200 amp relay / 240 volt single phase

by gar
Replies
12\$\$
Views
268

### 150417-0843 EDT Buck Parrish: Why does your...

150417-0843 EDT

Buck Parrish:

Why does your customer want to switch off this entire subpanel? What are the actual loads? How many circuits?

Rather than a single contactor you could consider...
3. ## Thread: THE PHYSICS of . . . . MAGNETIZATION-CURRENT INRUSH

by gar
Replies
21\$\$
Views
868

### 150416-2555 EDT A basic equation to this...

150416-2555 EDT

A basic equation to this problem is the differential equation:

vsource = i*R + K*N*dPhi/dt

v is the driving source voltage
i is the magnetizing current
R is the series loop...
4. ## Thread: low voltage lighting wired in series not working unless first switch is turned on

by gar
Replies
2\$\$
Views
106

### 150416-2352 EDT I do not understand your...

150416-2352 EDT

I do not understand your description. You need to draw a diagram of the circuitry on the 24 V side of the transformer. The transformer is of no importance to your problem. It is...
5. ## Thread: THE PHYSICS of . . . . MAGNETIZATION-CURRENT INRUSH

by gar
Replies
21\$\$
Views
868

### 150415-1933 EDT Bugman1400: I provided a...

150415-1933 EDT

Bugman1400:

I provided a portion of one B-H curve in post 6. This was a hysteresis curve. Basically there are two types of B-H curves generally presented. These are...
6. ## Thread: Relay coil resistance

by gar
Replies
8\$\$
Views
351

### 150415-1702 EDT jason619: Go to the...

150415-1702 EDT

jason619:

Go to the following location and download the datasheet. This is for the P&B KUP relay family.
...
7. ## Thread: THE PHYSICS of . . . . MAGNETIZATION-CURRENT INRUSH

by gar
Replies
21\$\$
Views
868

### 150413-1514 EDT Phil: Please describe your...

150413-1514 EDT

Phil:

Please describe your statement What were the initial conditions for the "case above". From this very loose statement how do you conclude "twice"?

What is the meaning of...
8. ## Thread: Relay coil resistance

by gar
Replies
8\$\$
Views
351

### 150412-2360 EDT Upnorth: In general you can...

150412-2360 EDT

Upnorth:

In general you can not just use a relay with a higher resistance coil to reduce power dissipation and do the same mechanical job (work).

Within some limited range...
9. ## Thread: THE PHYSICS of . . . . MAGNETIZATION-CURRENT INRUSH

by gar
Replies
21\$\$
Views
868

### 140411-1706 EDT Phil: At 60 Hz eddy current...

140411-1706 EDT

Phil:

At 60 Hz eddy current (also called Foucault current) and hystersis losses are about equal. This is achieved by the selection the core material and the lamination...
10. ## Thread: THE PHYSICS of . . . . MAGNETIZATION-CURRENT INRUSH

by gar
Replies
21\$\$
Views
868

### 150411-0844 EDT Phil: This is not obvious...

150411-0844 EDT

Phil:

This is not obvious and not correct, if I understand what you said. Refer to Attwood's hysteresis graph that I presented in post #6.

11. ## Thread: remote control switching

by gar
Replies
7\$\$
Views
348

### 150410-0929 EDT Study the Insteon website. ...

150410-0929 EDT

Study the Insteon website.

A wall switch, and I believe there are several types (relay, solid-state, dimmable), are locally switchable at the switch location, and are remotely...
12. ## Thread: remote control switching

by gar
Replies
7\$\$
Views
348

### 150409-0855 EDT You have two choices for...

150409-0855 EDT

You have two choices for switch replacements that don't require any new wiring. X10 type switches that use PLC (power line communication), or RF communication. Insteon is a PLC...
13. ## Thread: remote control switching

by gar
Replies
7\$\$
Views
348

### 150408-2350 EDT I don't understand the...

150408-2350 EDT

I don't understand the requirements.

There are 10 outside lights to be controlled from many locations. These are not all fed from the same circuit source.

What is not clear...
14. ## Thread: Cable capacitance and relays

by gar
Replies
5\$\$
Views
220

### 150408-1629 EDT Define a control cable? I...

150408-1629 EDT

Define a control cable?

I can send 115.2 kbaud data over 4000 ft. I can send simple DC signals over thousands of feet. Note 5280 feet is 1 mile. I can send data over long...

by gar
Replies
2\$\$
Views
187

### Energy cost

150408-1139 EDT

My energy cost for last year was:

\$ 0.162 / kWh for electricity.
\$ 0.847 / CCF for natural gas.

There are 29.31 kWh per 1 CCF.

Cost of natural gas in kWh is:
16. ## Thread: Need ideas, dimming 72 recessed

by gar
Replies
7\$\$
Views
435

### 150407-2205 EDT chris kennedy: You can not...

150407-2205 EDT

chris kennedy:

You can not do it from two analog pots unless the highest or alternatively the lowest was to dominate. Thus, there has to be a stepping type control, or another...
17. ## Thread: THE PHYSICS of . . . . MAGNETIZATION-CURRENT INRUSH

by gar
Replies
21\$\$
Views
868

### 140407-1550 EDT Following is a part of what I...

140407-1550 EDT

150405-1412 EDT

GoldDigger:

On reflection I want to try to clarify flux or flux density in a...
18. ## Thread: Inrush current effects on sizing Transformer and/or Diesel

by gar
Replies
4\$\$
Views
263

### 150407-0830 EDT Electric motors, generators,...

150407-0830 EDT

Electric motors, generators, transformers, and resistance heating elements can tolerate rather large short time overloads. DC motors and generators 10 times or more, except some...
19. ## Thread: Theory Amps and Watts

by gar
Replies
37\$\$
Views
1,256

### 150406-1903 EDT Strathead: Power is not...

150406-1903 EDT

Power is not work. Power is the rate of doing work. The integral of power over time is work. Mathematical integration is the summation of small increments over some...
20. ## Thread: Theory Amps and Watts

by gar
Replies
37\$\$
Views
1,256

### 150405-2424 EDT Time out limits are a major...

150405-2424 EDT

Time out limits are a major problem on this form. Thus, I won't recompose what I had tried to add.

Go to my wesite http://beta-a2.com/energy.html and view graphs 9.8.2.2 and...
21. ## Thread: Theory Amps and Watts

by gar
Replies
37\$\$
Views
1,256

### 150405-2344 EDT zcanyonboltz: I have not...

150405-2344 EDT

zcanyonboltz:

I have not read all the posts so I may be repeating what has been said.

Watts (power) is a measure of the rate of doing work. This is like the speed of a car....
22. ## Thread: Tranny inrush formula?

by gar
Replies
31\$\$
Views
761

### 140405-2153 EDT chris: An unloaded...

140405-2153 EDT

chris:

An unloaded transformer has an inrush current that is not the same every time power is applied to the transformer. The inrush can be all over a large range. The value...
23. ## Thread: Tranny inrush formula?

by gar
Replies
31\$\$
Views
761

### 150405-2121 EDT GoldDigger: I should have...

150405-2121 EDT

GoldDigger:

I should have been more clear. Hysteresis can not be ignored. The magnetizing current drives the ferromagnetic material to some flux level. When the magnetizing...
24. ## Thread: Tranny inrush formula?

by gar
Replies
31\$\$
Views
761

### 150405-1929 EDT chris kennedy: My...

150405-1929 EDT

chris kennedy:

My suggestion is that you contact the transformer manufacturer and ask for a recommended breaker.

As an approximation a switch,...
25. ## Thread: Tranny inrush formula?

by gar
Replies
31\$\$
Views
761

### 150403-9840 EST Not really. However, there may...

150403-9840 EST

Not really. However, there may be some emperical ratios that are used relative to transformer kVA, and the type of transformer.

In a sense the real question is what is the...
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