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The 300 foot (100 meter) limit on copper for the ethernet. I have had to go further and I have used a two port POE switch to divide the longer runs into two segments.
The POE power supply is on one...

Many electricians have not had experience with harmonics and transients. I can assure you that thes problems are real life in many applications and are of greater concern where non-linear loads are...

The Fluke 43 series (43, 435 436 437) power quality meter is what I would use, but the cost is pretty high for occasional use. I am in a little different business and we can justify top tier test...

I would have deleted the double post entirely if I could figure out how to do it!

But the Fluke 190-204S has 4 isolated inputs.
Also I realy was also talking about the metal chassis on the old AC powered oscilloscopes where you also had to remove the safety ground to work with...

If you need one there is nothing else that comes close. If I had to set up an oscilloscope in some industrial applications it can be really a pain and also dangerous. The danger comes from the need...

Thanks.

I remember reading about a bypass of the evaporator coil to reduce the tem of the coi, increase run time etc to lower the humidity in the house. my question is how much what are the relative benefits...

You are quite correct. Whenever three phase is involved the square root of three has got to be in there somewhere.
I am sorry, I really did not look at the motor dataplate very closely.

It is a 5 HP at 208/230 and a 5 hp at 460 as well/
It is a 3 hp on 50 HZ since it is running slower The voltages are also different at 50HZ.
A 1800 rpm motor at 60 HZ runs at 1500 rpm on 50 HZ....

Following is a quote from Wikkipedia on legionaires disease.
If you have not treated the water in the cooling tower it presents the danger of becoming a source of Legionella. Very BAD.
The...

You have to remember the chamical guy gets paid on how much you buy, not what you need to buy.
There are many things that have to be taken into account and perhaps a good water treatment company can...

I hope you guys don't consider this too DIY for the forum, but here goes.
As a control professional in industrial applications I have wondered about the Comfort Net on my Amana heat pump. I think...

Too old and set in our ways to do that and it takes clicking the mouse button and not the keyboard backspace.
Also hadn't thought of it either. So There!

We have a small office /operations building with a Trane package unit and Trane VariTrac CCP system. In the three years I have been in the building I have been comfortable for perhaps part of a day....

I get so many double click and and googleads etc that this site is a real PITA.
I may quit checking on what is happening if it gets worse.
I have tried adding the offending sites to the restricted...

We have plenty of A/C for the control room.The air will be drawn fronm outdside of the control rooms / server rooms. The air will be considerably hotter than what is inside, but either I add a single...

Allen bradley sold bare drives you could build what you wanted and also packaged drives that included the control wiring and bypass contactors. Get the numbers off of the enclosure and call your...

I think the 1336 has an automatic restart after power loss feature.
The following link will take you to the AB.com search page:...

I am leaning on installing the Williams unit inside the control room and using one hole sawn through the filled block wall to draw in outside air with a damper to control the amount of outside air....

It sounds to me like the coild are going bad because the starter is not pulling in completely and the solenoid is not closing the magnetic circuit. The coil pulls down the "core" of the solemoid to...

The cost of the newer VFDs has come down a lot in the last 10 years and the usability has increased many times. The user interfaces are better,too.
Thes new drives are also pretty relaible.
If you...

Most of the new VFD drives are made using surface mount technology for the parts on the circuit boards. The smaller ones are probably not economically repairable. The larger units have replacement...

Thanks for the suggestions. I think that the 400 CFM @0.6" H20 is enough to pressurize the 4 rooms in the building There are two doors and no windows. One exhaust fan in the restroom seems to be on...

I will look into the MovinCool for future applications.
We inherited the control room setup from our client. We operate the water treatment and cooling circuits for a major new steel mill and melt...

We don't have that choice since the three rooms that comprise the office area are all together. The area where the computers and PLCs are is at one end of the building (within the unairconditioned...

I have two industrial control rooms where the plant control PLCs and HMI computers are located.
This area was built with mini-splits for heating and cooling. My problem is the dust that enters the...

I am sorry, I meant to type spdt. That is a single pole double throw relay. I just bought some from an electronics distributor last week.
What that means is there is a common input that is switched...

Install a dpst relay and use the common and normally closed contact.

This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread....

I had thought it would be handy and to some extent it is, but not if the darned thing leaks.
I don't mind using a copper line for evacuation and installing a tee to tie the service port to the...

There are megohm meters and meggers. The best test would not be from a VOM, even digital, at the low voltage these instruments use. A megger or equivalent that tests the resistance at 500VDC is...

I just purchased an SMAN3 for my maintenance department and happend to have occasion to use it at my home during installation of a new heat pump.
I found that I hav a very difficult time in drawing...

It would depend on the size of the receiver tank and the compressor and the desired regulation.
For our air screw compressors they unload at 98 PSI and load at 93 PSI.
It would depand on the...

In my opinion the use of contactors downstream of the VFD is poor practice.
That being said there needs to be overload protection for each individual motor and that would imply contactors, but these...

Whit most modern VFDs you can set up a minimum speed and send the measured variable to the drive as a 4-20 mA analog signal and let the drives control to meet your setpiont.
The drives I use are for...

The control coils refer to the discrete output points
the discrete inputs are just that
holding registers are 8 bit bytes that are located in the memory
the input registers are the 8 bit bytes...

I would like to have the filtration improved for my house. 1750 sq ft in Mobile AL.
I currently have a Bryant 310AAV036070 gas furnace with a 3 ton Carried airconditioner condenser.
I am having the...

This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread....

Check the register addresses for those data points. If you have the other data in a modbus read then thr ones you are missing may have incorrect addressing.
The single points are usually bit mapped...

I installed the WR Big Blue touchscreen with humidty control and I like it. My wife gets confused sometimes, but that is fairly normal with technical things. The auto feature is nice this tim of year...

I just had a Goodman system installed and it meets the rebate standards.
The heat pump is an SSZ16 4 ton unit, matching coil and a GVM 115K but variable speed gas furnace.
The only thing I don't...

I have a Goodman GMV with heat pump and the variable speed fan is great! It ramps up smoothly and offers the benefits previously mentioned and also if your thermostat supports it it can have...

It is very possible that you have a small leak elsewhere and you are receiving a BS diagnosis. I have seen this a number of times.
The last time the tech said that the coil was leaking and needed...

Since the comfortsence module was mentioned for the Copeland scroll I have a question for the group. I am not familiar with the units, but have read about rhe 3 pahse units that are applicable for...

NOTHING will protect from a direct lightening hit on the lines near a house.
Many times the damage is done by common mode voltages between "grounds" of different potentials.
You should install...

I think that a major reason that the cost may be higher is lack of understanding of the GE ECM system. Initially there were problems with magnets coming off, but that has been solved. The problems...

I don't know what you are after, but years ago I investigated using the crawlspace as a plenum. The idea is the seal and insulate the foundation walls and cover the dirt floor with an impermable...

I don't know if there is a possibility of having a filter too large. The limits would be a filter size that takes up too much room. The pressure drop across the filter is related to area of the...

Don't worry about the problem now. If you have problems at low airflow settings, then find a solution. Have the installer come up with an answer and have an agreement in principle at least before you...