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cakabo28
13-04-2007, 10:49 PM
hı everybody.
ı am new member.
What do you think about following compressors?
which is the best?
panasonic-rechi-hitachi

Brian_UK
13-04-2007, 10:56 PM
Hi Cakabo and welcome to the forum.

Which type of service do you want these compressors for ?

cakabo28
14-04-2007, 09:22 PM
hı brian,
for air-conditioner and rotary types comparison

RickSter
31-03-2008, 12:35 AM
Have a look at Manurop compressors. They're out of France but are very strong and can handle floodback without any problems

nike123
31-03-2008, 12:43 AM
Have a look at Manurop compressors. They're out of France but are very strong and can handle floodback without any problems

I think that Maneurop doesn't produce rotary compressors. They do make scroll compressors.

Brian_UK
31-03-2008, 11:53 PM
It is also about a year since the question was asked and we haven't had another answer back from the original poster.

cakabo28
15-04-2008, 01:59 PM
yes u are right
what a pity

OzCool
22-04-2008, 10:45 AM
i tend to find Manurop & Copeland compressors to be the most reliable.

jong0726
02-05-2008, 09:22 PM
i think its panasonic

jvdwaalv
09-05-2008, 09:47 PM
I use maneurop as well as Copeland scroll compressors at various applications. The copeland prove to be more reliable, as extra benefit is the noise level much lower

suny
19-05-2008, 08:54 AM
Hi! Cakabo28

Take extra precautions if you use Manurop compressors if you use them on very low temperature applications. On medium & high temperature applications they are perfectly Ok, but if you use on low temperature applications you must not allow head temperature to increase more than 48 deg. C. If it goes beyond this, the mechanical parts will be wasted with in no time. I agree with RicKster, it can handle flood back & strong.

I have burnt my fingers using Manurop LTZ compressor with R 404a on a low temperature application. During a long week end on Thursday evening it was working perfectly Ok. Monday morning I found that the room temperature was only -5 deg C. & compressor overload was tripped off with high & low pressure standing at 180 & 15 psi respectively.

Then it was observed that there was a gas leak on the connection capillary tube to the low pressure cutout and fair potion of the R 134a has leaked out from the system, which resulted the head temperature to increase and wasted compressor mechanical parts. Please see the attached photo for your information. Due to overheat the gadjen pin lock got wasted and the gadjen pin fallen on to the piston sleeve, which grooved the sleeve.

BESC5240
19-05-2008, 01:22 PM
Hi! Cakabo28

Take extra precautions if you use Manurop compressors if you use them on very low temperature applications. On medium & high temperature applications they are perfectly Ok, but if you use on low temperature applications you must not allow head temperature to increase more than 48 deg. C. If it goes beyond this, the mechanical parts will be wasted with in no time. I agree with RicKster, it can handle flood back & strong.

I have burnt my fingers using Manurop LTZ compressor with R 404a on a low temperature application. During a long week end on Thursday evening it was working perfectly Ok. Monday morning I found that the room temperature was only -5 deg C. & compressor overload was tripped off with high & low pressure standing at 180 & 15 psi respectively.

Then it was observed that there was a gas leak on the connection capillary tube to the low pressure cutout and fair potion of the R 134a has leaked out from the system, which resulted the head temperature to increase and wasted compressor mechanical parts. Please see the attached photo for your information. Due to overheat the gadjen pin lock got wasted and the gadjen pin fallen on to the piston sleeve, which grooved the sleeve.

This is confusing to me:

Is there R134a in the system : then you should not use it in an LTZ compressor (LBP application ???).

Is there R404A in the system : what is you HP-switch setting?

If there is a leak in the system, and refrigerant lost, I would think the compressor would cut out on LP-switch.

Air can only come in to the system if you work below 0 bar (gauge pressure) or if maintanence/repair/evacuation is not done properly ...

If condensing pressure was too high, the HP switch should have cut out the compressor (and this would not be a cause of break down). Don't tell me you use a HP-switch with automatic reset. This is not a safety switch then. If you don't use a manual reset HP-switch, it is your choice to kill the compressor ...

It seems to me that the reason why the compressor broke is that there was a leak in the system and not enough safety build in the system to prevent the compressor to break ...

I know of thousands of Maneurop compressors running on condensing temperature of 48C and above ...

suny
19-05-2008, 06:11 PM
It is R 404a system. HP & LP setting 300 & 02 psi. Yes, there was very minute leak (Please note this). Yes, there was a refrigerant loss & 15 psi pressure in low side. Therefore it did not cut off from LP switch. Due to 15 psi pressure it can not take air in to the system. It is a manual reset HP switch. The system was working for two years with out any problem. The evaporating temp was at -35 deg C, Working HP 255 psi, LP 18 psi, ambient temp 30 to 35 deg C, Compressor dome top temp 45 to 48 deg C.

All other MT compressors of mine are working perfectly at the moment.

BESC5240
20-05-2008, 03:37 PM
No compressor (Maneurop or other) breaks down just because it runs at Tc=48C. There must be something else.
Prpably it has something to do with the suction superheat (and as a consequence: motor cooling, discharge temperature).

Officially the maximum superheat for LTZ compressors running on R404A is 30K. In this case (Tc=48C and To=-35C) I would allow max. 40 K superheat. But only as an exception !!! Standard, it should be around 20K.

If you have a leak/ shortage of refrigerant in the system, it will surely lead to excessive superheat ...
The internal compressor protection will cut out eventually, but it will reset (after quiet a while) automatically ...
In the end the compressor (Maneurop or any other with an automatic reset motor protection) will break ...
if there has been no other warning (like temperature alrm in the cold room ...).

US Iceman
20-05-2008, 04:08 PM
I have not been following this thread, but just happened to notice some recent comments on a certain brand of compressor.

Before judgements are made on a specific brand or type of compressor I think it is important to remember an important concept:

Compressors fail for specific reasons. Sure, a defective compressor may be found occasionally, however the majority of compressor failures are the result of misapplication of the compressor or an external fault which the compressor operates with. The external fault may be leaking refrigerant, electrical supply, low or no suction or discharge superheat (depends on whether the compressor is a screw, scroll, or recip), high or low suction pressures, or high discharge pressures.

And there are probably more conditions which could be listed here.

Therefore, it's important to remember that when a component fails it failed for a specific reason. It may not have been defective to start with, but it failed due to other factors. So blaming the component for the failure and saying that type of compressor or that brand of compressor is bad is NOT correct. Something else caused the failure.

I see this a lot where people blame a certain component for repeated failures and say; "that equipment is no good". In almost every case the original problem was with the installation, maintenance practices used, or an improper selection or design.

Manufacturers do not make bad products! People apply them badly....:rolleyes:

The compressor may break, but it's not the compressors fault it broke. Something else caused it.

Lowrider
20-05-2008, 11:15 PM
.

Before judgements are made on a specific brand or type of compressor I think it is important to remember an important concept:


Manufacturers do not make bad products! People apply them badly....:rolleyes:

The compressor may break, but it's not the compressors fault it broke. Something else caused it.

Sorry fo removing some of it! But I do agree with you on this!

And an other thing:

I think that Maneurop doesn't produce rotary compressors. They do make scroll compressors.

Looks like one in the picture!

US Iceman
21-05-2008, 01:23 AM
That's OK Lowrider.

You posted the most important part!;)

nike123
21-05-2008, 07:29 AM
Looks like one in the picture!
This on picture is LT/LTZ or MT/MTZ or NTZ and it is reciprocating!;)

http://farm3.static.flickr.com/2107/2509967495_7e6a53cf26_b_d.jpg

Lowrider
21-05-2008, 11:58 PM
Here we go again! Language difference!

Back to the creators of problems!
Just had a discussion with a controls firm about a chiller plant with four of our chillers. One chiller is running and making 11 deg C of water, setpoint is 10. Pump of the second chiller is started and a minute later the chiller is started. After about 30 seconds of running, the chiller is stopped, a minute later the pump. Between 1 and 2 minutes later the pump is started again, the chiller started again, left running for 20 seconds, and so on.

Machine's are from 1989, made 30000 starts from start up until mid 2007. From mid 2007 until the end of 2007 the counter was 39000!

The controls firm made changes is the system when excessive starting began and when asking them about it told us whe had to have restart inhibbiters in the machine's to prevent this.

Nowadays we do and turn them on when needed, simply to keep this from happening. Controls and counter measures in our machine's are getting more and more extended to keep them in one piece and protect them from "cowboys"!

US Iceman
22-05-2008, 01:18 AM
This is :off topic:, but I wanted to respond to Lowriders post.



...Pump of the second chiller is started and a minute later the chiller is started. After about 30 seconds of running, the chiller is stopped, a minute later the pump. Between 1 and 2 minutes later the pump is started again, the chiller started again, left running for 20 seconds, and so on.


Now that is how you don't control energy use! A controls company who is controlling chillers in a rather bad way I might add. And since these are probably large chillers they also add can significant kW demand to the energy bills.

Let me guess... with that control scheme they are controlling water temperature only?

And as it appears they made a bunch of changes and when those changes made bad operating sense, they told you you had to do something different?!

If this was not such an sad story it would almost be funny.

suny
23-05-2008, 10:50 AM
Dear BESC5240

Thank you very much for your comments. Yes I know that this can not break under these conditions. That is why I posted this to you all experience guys to find out the reason for failure. After this I have stopped buying this brand for my low temp applications. For your information in our country there are more failures only on this model. Furthermore they have stopped production of this model. According to the local agent now they are marketing NTZ series.

Furthermore I have said that, due to the long weekend it nobody was there it detect the problem. I feel that was the only part from my side with regard to the failure.

It did not cutoff from H or L PC, Compressor 3 Pole contactor overload. There may be a possibility to cut off from the internal thermal overload. Please explain.

BESC5240
23-05-2008, 02:12 PM
Dear BESC5240

According to the local agent now they are marketing NTZ series.



It did not cutoff from H or L PC, Compressor 3 Pole contactor overload. There may be a possibility to cut off from the internal thermal overload. Please explain.

NTZ is an improved/upgraded version of the LTZ.
Main differences are:
- bigger (more powerfull) electromotor allowing the compressor to work at higher evaporating temperatures (max. -10C)
- more efficient electromotor
- better tolerance between piston and valve plate.
This increases the overall performance/efficiency of the compressor (specifically at -35C/ +40C).

The compressor has it's own internal protection. This will reset automatically when the compressor has cooled down. This can take several hours depending on the conditions and the size of the compressor. While the compressor is shut down, the room temperature will rise. The temperature rise depends on the load.

3 things have an influence on the discharge temperature Td of a compressor (and as a result the 'temperature od a compressor'):
- suction pressure, Po . If Po ↓, Td ↑
- condensing pressure , Pc . If Pc ↑, Td ↑
- suction gas temperature, Tsg. If Tsg ↑, Td ↑.

So if there is a lack of refrigerant fead to the evaporator (a leak, or an obstruction in the liquid line, ...) :
- Tsg ↑ ,
- Po ↓,
- and Pc ↑.
All of this lead to an overheated compressor...

Lowrider
23-05-2008, 09:12 PM
This is :off topic:, but I wanted to respond to Lowriders post.



Now that is how you don't control energy use! A controls company who is controlling chillers in a rather bad way I might add. And since these are probably large chillers they also add can significant kW demand to the energy bills.

Let me guess... with that control scheme they are controlling water temperature only?

And as it appears they made a bunch of changes and when those changes made bad operating sense, they told you you had to do something different?!

If this was not such an sad story it would almost be funny.

Last one :off topic: . Controlling multiple chillers is still diffucult for a lot of people! Here there were 4 chillers of 500kW each, serving a telecom centre.

setpoint chw to building 10 dgr C, add band 0,5 no wait time, 13 dgr to building all chillers on. SP = chw to building, substract chiller, no wait time, then wait time of 5 minutes. Should be called non-controls company!

US Iceman
23-05-2008, 09:25 PM
My last comment on this also.:off topic:



Should be called non-controls company!


LOL. That's exactly right. Some think a controls company will actually improve the situation because ... afterall they are experts on controlling things (which means turning equipment on & off).:D

Lowrider
23-05-2008, 10:52 PM
I'm doing controls now at Trane. The system and set up we use prevent the machine's from being controlled on/off like many of the other do!

Only thing is, it's a secret how!

mazbut
23-05-2008, 10:59 PM
Hello

could someone here please explain what a chit on a compressor (V-type , make VEB Germany) indicates when it says

1.Refrigerant: CF2CL2 ( that's refrigerant I get it) but it is not listed in some books ,,,what's its another name and properties??

2. Suction minus 15deg C/+40 degC/ +20 deg C.......what does it mean? How can I reduce its final temp ie +20 to minus 20 C or so??

3. Given above conditions it has capacity of 11000 Kcal/hr,,,,what will be its capacity at minus 20 C final air temp?

4. It is meant to use with 9 KW motor,,,,belt driven.

please let me have your comments and answers to my query as I have to employ these compressors for cold rooms with sub zero F temp for storing prefrozen fish


thanks

botrous
27-05-2008, 11:23 PM
First of all hi my old friend US Iceman. . . and sure hi to all.
Most of you don't know me but some do and are really great friends :) , it has been a long time I didn't appear here in the best forum but I'm planning to get back . . .

Controls :

ON/OFF : For example, a thermostat is a simple negative-feedback control: when the temperature (the "measured variable" or MV) goes below a set point (SP), the heater is switched on. Another example could be a pressure-switch on an air compressor: when the pressure (MV) drops below the threshold (SP), the pump is powered. Refrigerators and vacuum pumps contain similar mechanisms operating in reverse, but still providing negative feedback to correct errors.

Simple on-off feedback control systems like these are cheap and effective. In some cases, like the simple compressor example, they may represent a good design choice.

In most applications of on-off feedback control, some consideration needs to be given to other costs, such as wear and tear of control valves and maybe other start-up costs when power is reapplied each time the MV drops. Therefore, practical on-off control systems are designed to include hysteresis, usually in the form of a deadband, a region around the setpoint value in which no control action occurs. The width of deadband may be adjustable or programmable.


Propotional : The proportional term makes a change to the output that is proportional to the current error value. The proportional response can be adjusted by multiplying the error by a constant Kp, called the proportional gain.

The proportional term is given by:
http://upload.wikimedia.org/math/3/f/8/3f80d26e2e621e0f123bb26e80e609e5.png

Where

Pout: Proportional output
Kp: Proportional Gain, a tuning parameter
e: Error = SP − PV
t: Time or instantaneous time (the present)

Plot of PV vs. time, for various values of KpA high proportional gain results in a large change in the output for a given change in the error. If the proportional gain is too high, the system can become unstable (See the section on Loop Tuning). In contrast, a small gain results in a small output response to a large input error, and a less responsive (or sensitive) controller. If the proportional gain is too low, the control action may be too small when responding to system disturbances.

In the absence of disturbances, pure proportional control will not settle at its target value, but will retain a steady state error that is a function of the proportional gain and the process gain. Despite the steady-state offset, both tuning theory and industrial practice indicate that it is the proportional term that should contribute the bulk of the output change.


http://upload.wikimedia.org/wikipedia/commons/2/2b/Change_with_Kp.png

Derivative : The rate of change of the process error is calculated by determining the slope of the error over time (i.e. its first derivative with respect to time) and multiplying this rate of change by the derivative gain Kd. The magnitude of the contribution of the derivative term to the overall control action is termed the derivative gain, Kd.

The derivative term is given by:
http://upload.wikimedia.org/math/c/0/4/c04b8da61877479253f5d345bf81e2a2.png


Plot of PV vs. time, for various values of KdWhere

Dout: Derivative output
Kd: Derivative Gain, a tuning parameter
e: Error = SP − PV
t: Time or instantaneous time (the present)
The derivative term slows the rate of change of the controller output and this effect is most noticeable close to the controller setpoint. Hence, derivative control is used to reduce the magnitude of the overshoot produced by the integral component and improve the combined controller-process stability. However, differentiation of a signal amplifies noise and thus this term in the controller is highly sensitive to noise in the error term, and can cause a process to become unstable if the noise and the derivative gain are sufficiently large.

http://upload.wikimedia.org/wikipedia/commons/c/c7/Change_with_Kd.png

Integral : The contribution from the integral term is proportional to both the magnitude of the error and the duration of the error. Summing the instantaneous error over time (integrating the error) gives the accumulated offset that should have been corrected previously. The accumulated error is then multiplied by the integral gain and added to the controller output. The magnitude of the contribution of the integral term to the overall control action is determined by the integral gain, Ki.

The integral term is given by:
http://upload.wikimedia.org/math/d/5/9/d593c27abdc1aecffb56d06d2a9ba8e3.png


Plot of PV vs. time, for various values of KiWhere

Iout: Integral output
Ki: Integral Gain, a tuning parameter
e: Error = SP − PV
τ: Time in the past contributing to the integral response
The integral term (when added to the proportional term) accelerates the movement of the process towards setpoint and eliminates the residual steady-state error that occurs with a proportional only controller. However, since the integral term is responding to accumulated errors from the past, it can cause the present value to overshoot the setpoint value (cross over the setpoint and then create a deviation in the other direction). For further notes regarding integral gain tuning and controller stability, see the section on loop tuning.

http://upload.wikimedia.org/wikipedia/commons/c/c0/Change_with_Ki.png

Summary
The output from the three terms, the proportional, the integral and the derivative terms are summed to calculate the output of the PID controller. Defining u(t) as the controller output, the final form of the PID algorithm is:


and the tuning parameters are

Kp: Proportional Gain - Larger Kp typically means faster response since the larger the error, the larger the Proportional term compensation. An excessively large proportional gain will lead to process instability and oscillation.
Ki: Integral Gain - Larger Ki implies steady state errors are eliminated quicker. The trade-off is larger overshoot: any negative error integrated during transient response must be integrated away by positive error before we reach steady state.
Kd: Derivative Gain - Larger Kd decreases overshoot, but slows down transient response and may lead to instability due to signal noise amplification in the differentiation of the error.

Source of information:http://en.wikipedia.org
For full text go to : http://en.wikipedia.org/wiki/PID_controller#Proportional_term

Hope this clarify control methodes . . .
Other and combinations of controls exists . . . . .

Respects and regards

icecube51
03-06-2008, 10:45 PM
i think there's a oil problem whit that type of compressor.its not enough lubricated. check if the oil is coming back???
most of the time the compressors are just worn out and not burnd ore crankt.

icecube51
03-06-2008, 10:55 PM
mazbut,
cf2cl2 = R12
see for tables and charts in the prog "coolpack"

grtz, Ice

yangchenchen
04-06-2008, 07:01 AM
who is the best football player in the world? Pele or Maradona?there is no exclusive answer.

ice_cool
11-11-2008, 09:42 AM
panasonic is good in fridge. hitachi is good in ac.

havertyp
23-11-2008, 01:19 AM
I have approx 10 autocascade portable temperature forci ng systems on my circuit, these are used in a design lab, and a lot of them are never switched off. They use the Maneurop LTZ compressor and I am quite amazed at their reliability, I have seen intervals of up to 6 - 8 years of quite tough operating conditions. The compressor burnouts I experienced were due to external factors, e.g. condenser fan failure and dirty condensers (the customer does not believe in regular maintenance..). Amazingly, there is no HP cutout on these systems, which would protect against this. I have seen another failure on an 8 year old LTZ which had an inlet valve failure, so motor running great, but no pumping.

ryanzhao
02-01-2009, 04:38 AM
Lanhai Compressor its good. especliay the horizontal compressor , DC compressor for the vehicle air condtioner,

Kaka
19-08-2009, 06:44 PM
Panasonic rotary is the best!