how do 2 speed compressors work??

[hugodrax]

Just curious on what goes under the hood, these 2 speed compressors work both in 4 ton then 2 tons by using less pumps? but the motor still spins at the same time right?

when they run at 1st speed does it consume less power or the same but just lower tonnage

also when running a two speed does it kick in on high gear, cool down the home lets say from 85 to 74 then switch to the low speed mode just to maintain the house temp and occasionally kick back the high speed when temps creep up VS a single speed which would just cycle on and off.

Anyhow between the speed capability of the indoor fan coil and the exterior compressor with 2 speeds it looks like a lot of calculations must go on I read that this infinty system measures the outside temp and inside temp to determine I guess comfortlevel etc..

Also anyone know what is the filter size the 05 FE4 model uses(4 ton) I want to stick in a good 3m filter in it (Filtrete Ultra Allergen) this should be fine with the FE4 Handler correct. or will it mess with the system performance?

[mrcoolz4u]

Generally when a two speed motor starts up, both winding are energized then falls back to the selected winding speed.

for example Most compressors carry two winding the start winding and the run winding. At start up both winding are energized then the start winding is taken out of the circuit leaving the run winding in the circuit.

At start up the amp draw is higher because both winding is drawing current. so more current is being used.

this application applies generally to all multispeed motors.

this happens with the 3 and 4 speed motors as well. Compressors and fan motors

it starts at high speed then goes back to the selected speed.

[plain spoken]

There are more than one type of "2 speed" compressors. Since you are talking about Infinity I assume you are asking about the Carrier 2 speed Puron unit.

This compressor only has one motor winding and does always run the same speed, however it does use less electricity on low speed. When it is running in low there is less load on the motor so it does not have to work as hard, thereby using less power. The motor in this compressor can turn in both directions. When it turns one way it only pumps on 1 piston (low stage), when it turns the other way it pumps on 2 pistons (hi stage). The direction it turns is controlled by the control board in the outdoor unit that responds to commands from the thermostat.

Whether it runs in low or high depends on the call from the thermostat. The thermostat will make this decision based on how far the temperature in the space is from set point. When a proper load calculation is done, the system is sized to provide enough cooling or heating at the most extreme temperatures to maintain comfort in the space. Since most of the time it is not operating in these extreme conditions, the unit is usually oversized. With a 2 stage unit the unit can be better matched to the load at all conditions. If there is a larger demand for conditioning, the unit can run to the Hi capacity and when there is less demand it will run in Lo capacity.

The Infinity does not use the outdoor temperature to decide on staging. It does have an option you can turn on that when the outdoor temperature gets above a certain point (you decide what that point is) that it will automatically run only Hi capacity.

[Edited by plain spoken on 10-08-2004 at 01:52 PM]

[cashcow]

Plain Spoken: I've got a follow up question regarding your explanation of the thermostat high/low call.

Could you explain how the thermostat actually determines high or low speed?

For example, let’s say the stat is set to 75 and the temp in the space climbs to 76, creating a call for cooling. In this scenario would a 1 or 2 degree temp differential (between the set temp and acual temp) cause the unit to always start in low speed and then move into second stage if the thermostat can't be satisfied in X amount of minutes?

I'm also curious as to how the Infinity Fan coil operates. I.E. how the fan speed is determined by the thermostat. Is it the same principle as the heat pump?

[cashcow]

**Sorry double post**

[plain spoken]

How the thermostat works depends on the stat. There are a lot of different schemes of control used by various manufacturers. If you are asking about the Infinity, it is a calculated algorithum. It considers how far the temperature in the space is from set point, how long the unit has been running, or on a new call how long it has been off. It is not a fixed temperature, but changes with conditions. If you go over to the Infinity and change the setpoint, it resets all algorithums. At that point for the first call, .5 degree from setpoint brings on Lo.

Control of the fan speed with Infinity? The Infinity "talks" directly to the variable speed motor. It always knows what the cfm and speed the motor is operating at and tells the motor what it wants it to be at. The exact cfm will vary depending on several variables. If the Infinity senses that the humidity in the space is too high, it can tell the motor to slow down some in order to dehumidify the air. If it senses that the humidity is just a little high and the temperature is further away from setpoint it will adjust the motor speed again in order to try and reach temperature and humidity setpoint at the same time. It can speed it up for electric heat if needed. These are just a few of the variable it considers. It knows the best speed for all the variable it may encounter and commands the motor to run accordingly.

[cashcow]

Thanks Plain. Yes I'm asking about the Infinity system (controls, etc.)

How would the Infinity handle a temperature that is at set point, but high humidity. For example: Stat set to 75, space temp is 75, but humidity in the 60% range.

In that situation with a call for dehumidification would the Infinity run at low speed compressor, low speed fan?

[plain spoken]

If dehumidification option is turned on, then yes as long as your humidity set point is below 60%.

You select the humidity set point just like you select your temperature set point. You can turn dehumidification off or on, again a selection.

The design of the Infinity is to provide much greater than normal dehumidification (as well as many other controls and comforts). It provides this dehumidification in seveal ways. 1. Any time you have a call for cooling (temperature above setpoint), the Infinity system operates at a lower cfm range to dehumidify. 2. If the humidity is above your set point during this call for cooling, it will slow the fan even further to do more dehumidification. 3. If you do not have a call for cooling and the humidity is above the set point, it will bring the cooling on with a very low fan speed just to dry out the air. In other words it becomes like a whole house dehumidifier. In this mode there are a couple of limits. It will only over cool the space up to 3 degrees. Once the space gets below 75 degrees then the 3 degree ovecool is proportionally decressed.

[afton]

Originally posted by plain spoken
If dehumidification option is turned on, then yes as long as your humidity set point is below 60%.

You select the humidity set point just like you select your temperature set point. You can turn dehumidification off or on, again a selection.

The design of the Infinity is to provide much greater than normal dehumidification (as well as many other controls and comforts). It provides this dehumidification in seveal ways. 1. Any time you have a call for cooling (temperature above setpoint), the Infinity system operates at a lower cfm range to dehumidify. 2. If the humidity is above your set point during this call for cooling, it will slow the fan even further to do more dehumidification. 3. If you do not have a call for cooling and the humidity is above the set point, it will bring the cooling on with a very low fan speed just to dry out the air. In other words it becomes like a whole house dehumidifier. In this mode there are a couple of limits. It will only over cool the space up to 3 degrees. Once the space gets below 75 degrees then the 3 degree ovecool is proportionally decressed.


Plain,
You seem to know a lot about this subject. I have had a new Amana Ultron system installed with a two speed compressor, a two stage furnace and a varible speed blower. The installer used a White-Rodgers thermostat model 1F95-391.
This thermostat has all of the same control features you described about the Infinity. The thermostat has many points for connections but the installer only used five wires to hook up the system. My question is, is it possible to control a system with multiple speeds and stages (including humidity control) using only five wires. Thanks for any input.

[mark beiser]

Originally posted by mrcoolz4u
Generally when a two speed motor starts up, both winding are energized then falls back to the selected winding speed.

Actually, only the windings for the desired speed are energized. If you were to apply power to more than one of the speed taps in the motor, it would burn out the motor windings.


for example Most compressors carry two winding the start winding and the run winding. At start up both winding are energized then the start winding is taken out of the circuit leaving the run winding in the circuit.

I don't know of any compressors that drop the start winding out after startup. If it has a start kit, it will drop the start capacitor out, but the start winding will still be energized and have a run capacitor.
There are some fan motors out there that drop the start winding out after startup, but they are rare. The last one I saw was about 5 years ago on a very old 7.5 ton Westinghouse condensor with a belt driven condensor fan. A centrifical switch dropped the start winding out after it got up to speed.


At start up the amp draw is higher because both winding is drawing current. so more current is being used.

this application applies generally to all multispeed motors.

The amperage is higher at startup because the motor is pulling lock rotor amps. When induction motors start up, the amperage starts very high and goes down as it gets up to speed. It has nothing to do with how many windings are energized. Unless it is a part winding start motor, fairly rare, power is being applied to the same inputs when it is running as when it is starting...


this happens with the 3 and 4 speed motors as well. Compressors and fan motors

it starts at high speed then goes back to the selected speed.

Again, power is applied to only one speed tap at a time or bad things happen. Some higher horsepower motors used in big applications have some interesting sequences of operation, but fractional horsepower motors are started on the same speed tap/winding they are run on.

[mark beiser]

Originally posted by hugodrax
Just curious on what goes under the hood, these 2 speed compressors work both in 4 ton then 2 tons by using less pumps? but the motor still spins at the same time right?


Different manufacturers do it different ways.

plain spoken covered the Carrier Infinity way. Looks interesting, I have no experience with them though.

Lennox used to do it with a compressor that had two speed motor with two complete sets of start windings and a run winding with two speed taps. The compressor spins in the same direction for both stages, just at different speeds. Gota love those 2 stage 9 pole contactors with mechanical and electrical interlocks! After years of working on them, I still change those contactors out wire for wire, one wire at a time, lol.
Any units that used that Copeland 2 speed compressor worked that way.

The newer 2 stage scroll compressors spin at the same speed for both stages, but the compressor is partially unloaded for the first stage. Copeland has a neet flash vidio explaining how it works on thier web site.

Trane, ever the fan of the "bigger hammer" brute force method, just uses 2 different sized compressors. ;)

[hugodrax]

Thanks for the update, I could imagine the computer must be pretty powerful to figure this stuff out. I could only imagine it would be an expensive service call when some component goes bad :)

[plain spoken]

Should not be any different than any other service call. The components are really the same in the units, the Infinity controller is not that much more than a Thermidistat. The cost is having someone who is not familiar with the system trying to figure it out on your time. As long as you stay with a trained service tech you should be ok.

[plain spoken]

Originally posted by afton

Originally posted by plain spoken
If dehumidification option is turned on, then yes as long as your humidity set point is below 60%.

You select the humidity set point just like you select your temperature set point. You can turn dehumidification off or on, again a selection.

The design of the Infinity is to provide much greater than normal dehumidification (as well as many other controls and comforts). It provides this dehumidification in seveal ways. 1. Any time you have a call for cooling (temperature above setpoint), the Infinity system operates at a lower cfm range to dehumidify. 2. If the humidity is above your set point during this call for cooling, it will slow the fan even further to do more dehumidification. 3. If you do not have a call for cooling and the humidity is above the set point, it will bring the cooling on with a very low fan speed just to dry out the air. In other words it becomes like a whole house dehumidifier. In this mode there are a couple of limits. It will only over cool the space up to 3 degrees. Once the space gets below 75 degrees then the 3 degree ovecool is proportionally decressed.


Plain,
You seem to know a lot about this subject. I have had a new Amana Ultron system installed with a two speed compressor, a two stage furnace and a varible speed blower. The installer used a White-Rodgers thermostat model 1F95-391.
This thermostat has all of the same control features you described about the Infinity. The thermostat has many points for connections but the installer only used five wires to hook up the system. My question is, is it possible to control a system with multiple speeds and stages (including humidity control) using only five wires. Thanks for any input.

I am not famaliar with that system at all so I can not help you with it. I find it hard to believe it can do all the Infinity can do, we have only discussed a very small amount of what the Infinity can do. The Infinity only uses 4 wires, so I guess it is possible yours could work with 5.

[dash]

Amana is more like Thermidistat,not likely to "do it all" with 5 wires.IMO

[dash]

hugodrax,

3M filters are some of the most restrictive,the filter change light may come on often,with Infinity,if it does it's the filter(s) not Infinity.

I would recomend you get a good 4' pleated filter from your installer,instead.

[ken little]

Plain spoken,

You seem to be more knowledgeable than anyone with regards to variable speed equipment.

As such, perhaps you can tell me of the staging algorithms for the Carrier thermidistat control.

Is time the ONLY determining factor or does "progress towards the set point" count too?

For instance:

Say I am operating in the cooling mode and my set point is 72 degrees. The house temperature is 73 degrees. The stat turns the low stage of cooling on. After 15 minutes the house cools to say 72.5 degrees--does the higher stage kick in or does the lower stage continue to operate?

Scenario two:
The setpoint on the stat is 72 degrees. The temperature outside is going up quickly and the house heats up to 78 degrees. The stat turns on the high stage of cooling and the house cools to 73 degrees. Does the higher stage continue to operate until the stat is satisfied then turn the system off OR does the lower stage come on the "maintain the setpoint"?

Also--what role does the outdoor temperature sensor play with regards to staging and thermidistat operation?

[plain spoken]

Originally posted by ken little
Plain spoken,

You seem to be more knowledgeable than anyone with regards to variable speed equipment.

As such, perhaps you can tell me of the staging algorithms for the Carrier thermidistat control.

Is time the ONLY determining factor or does "progress towards the set point" count too?

For instance:

Say I am operating in the cooling mode and my set point is 72 degrees. The house temperature is 73 degrees. The stat turns the low stage of cooling on. After 15 minutes the house cools to say 72.5 degrees--does the higher stage kick in or does the lower stage continue to operate?

Scenario two:
The setpoint on the stat is 72 degrees. The temperature outside is going up quickly and the house heats up to 78 degrees. The stat turns on the high stage of cooling and the house cools to 73 degrees. Does the higher stage continue to operate until the stat is satisfied then turn the system off OR does the lower stage come on the "maintain the setpoint"?

Also--what role does the outdoor temperature sensor play with regards to staging and thermidistat operation?

1. If low stage is gaining toward setpoint, the unit will stay in low unless the space temperature is more than 5 degrees above set point.

2. The stat will shift the unit to low speed as it approachs set point. It is better to run in low for extended periods of time than to satisfy the call with high.

3. On the Thermidistat the outdoor sensor really has no input in the cooling mode. With a heat pump in heating mode, it does effect the staging of the electric strips and fan speed if you have Super Comfort Heat Mode enabled. It also effects the humidifier operation as well as it is used for reading the switch over temperature in a dual fuel application.

[beenthere]

Originally posted by dash
hugodrax,


I would recomend you get a good 4' pleated filter from your installer,instead.


I never saw a 4 foot pleated filter.LOL...

[dash]

Originally posted by beenthere

Originally posted by dash
hugodrax,


I would recomend you get a good 4' pleated filter from your installer,instead.


I never saw a 4 foot pleated filter.LOL...


That's 4 sq. ft for his three ton system.You,












got me there,4 inch thick pleated filter.MY bad!

[Mr Bill]

Originally posted by beenthere

Originally posted by dash
hugodrax,


I would recomend you get a good 4' pleated filter from your installer,instead.


I never saw a 4 foot pleated filter.LOL...

I have seen one 4' deep in dirt. Lol!

[dash]

Originally posted by mrbillpro

Originally posted by beenthere

Originally posted by dash
hugodrax,


I would recomend you get a good 4' pleated filter from your installer,instead.


I never saw a 4 foot pleated filter.LOL...

I have seen one 4' deep in dirt. Lol!


Yeah, 4 foot of dirt,that must be it!LOL

[beenthere]

Originally posted by dash

Originally posted by mrbillpro

Originally posted by beenthere

Originally posted by dash
hugodrax,


I would recomend you get a good 4' pleated filter from your installer,instead.


I never saw a 4 foot pleated filter.LOL...

I have seen one 4' deep in dirt. Lol!


Yeah, 4 foot of dirt,that must be it!LOL

See, i can read without my glasses, sometimes.

[mrcoolz4u]

Originally posted by mark beiser

Originally posted by mrcoolz4u
Generally when a two speed motor starts up, both winding are energized then falls back to the selected winding speed.

Actually, only the windings for the desired speed are energized. If you were to apply power to more than one of the speed taps in the motor, it would burn out the motor windings.


for example Most compressors carry two winding the start winding and the run winding. At start up both winding are energized then the start winding is taken out of the circuit leaving the run winding in the circuit.

I don't know of any compressors that drop the start winding out after startup. If it has a start kit, it will drop the start capacitor out, but the start winding will still be energized and have a run capacitor.
There are some fan motors out there that drop the start winding out after startup, but they are rare. The last one I saw was about 5 years ago on a very old 7.5 ton Westinghouse condensor with a belt driven condensor fan. A centrifical switch dropped the start winding out after it got up to speed.


At start up the amp draw is higher because both winding is drawing current. so more current is being used.

this application applies generally to all multispeed motors.

The amperage is higher at startup because the motor is pulling lock rotor amps. When induction motors start up, the amperage starts very high and goes down as it gets up to speed. It has nothing to do with how many windings are energized. Unless it is a part winding start motor, fairly rare, power is being applied to the same inputs when it is running as when it is starting...


this happens with the 3 and 4 speed motors as well. Compressors and fan motors

it starts at high speed then goes back to the selected speed.

Again, power is applied to only one speed tap at a time or bad things happen. Some higher horsepower motors used in big applications have some interesting sequences of operation, but fractional horsepower motors are started on the same speed tap/winding they are run on.

Thank you Mr mark for the correction and my appologies to anyone for posting the wrong info

[hugodrax]

When the house was open to the humidity and reached outdoor humid temps the unit ramped up to a super highspeed mode 1600CFM then once it got closer and closer it dropped. Now most of the time it is in stealth mode :) and on some occasions it kicks a midspeed mode. What is weird is having a cool house but not hearing the system Also I notice that temperatures stay very consistent. Even though the system is rated 15 SEER (4ton) I suspect my savings will be higher than due to this thing running slow. I notice the outdoor meter running slowly VS real fast using the old unit which was 3 tons.

I read these new multispeed systems record the cycles and optimize them for better efficiency, Pretty interesting technology overall.

[plain spoken]

I knew you would be happy.... Another satisfied customer.:) Enjoy your investment!

Hey, now does your wife understand your excitement?

[dash]

Originally posted by plain spoken
I knew you would be happy.... Another satisfied customer.:) Enjoy your investment!

Hey, now does your wife understand your excitement?

Plain,

Here we find, every customer,installer and tech,seems to love the Infinity.Oh,salesmen ,too!How about where you are?

[plain spoken]

Nothing but Raves about it. I have not heard one complaint, even from the "more seasoned generation" that normally can not work a programmable stat. It is the absolute best system I have ever seen.

[hugodrax]

Originally posted by plain spoken
I knew you would be happy.... Another satisfied customer.:) Enjoy your investment!

Hey, now does your wife understand your excitement?

hehe no she chuckles A guy thing :), I finally got her to go outside and check out the unit. I do notice a major difference in comfort with this system VS my old system or even other homes with Central AC. Best thing since salt on nuts hehe. People have asked me about the unit :)

The Unit looks heavy duty like a porcelain paint nice industrial design. Gave it a Wax with Zymol, Takes on a real good shine,feels silky smooth and water beads right off :)

[molabear]

Just finished installing two infinity units out here in Palm Desert. That's right next to Palm Springs, in a all electric development. The place was built in 1973 and had the original electric FAU's. And the A. C. unit's were just old. It was a corporate house, and I guess they didn't use it much in the summer. The Doctor that bought the place was renovating, and he started with the heating and air. The infinity's were a easy sale. One 3 ton and one 4 ton. Lined under the return air compartment with lined insulation board. And ordered custom FRAG's for pleated filters. My house is only four years old, but I know what I'm replacing the A. C. units with when they go. These units running 24/7 for five months a year, you are lucky to get eight years out of them. Those infinitys sure are nice.

[jacob perkins]

99999

[tony82164]

Originally posted by mrcoolz4u
Generally when a two speed motor starts up, both winding are energized then falls back to the selected winding speed.

for example Most compressors carry two winding the start winding and the run winding. At start up both winding are energized then the start winding is taken out of the circuit leaving the run winding in the circuit.

At start up the amp draw is higher because both winding is drawing current. so more current is being used.

this application applies generally to all multispeed motors.

this happens with the 3 and 4 speed motors as well. Compressors and fan motors

it starts at high speed then goes back to the selected speed. Motor speeds Induction motors-start-are made for use on 25,50 or 60 cycles (Hz) current.The speed of a motor depends on the cycles (Hz) and number of field poles.Motor speeds are calculated from the synchronous speed. Synchronous speed is related to rotating magnetic fields. (The Field advances one pole for every 1/2 cycle of current.)If the rotor can keep up with the rotating field,the motor runs at synchronous speed.for two-and four pole motors is. Motor speed-RPM 2 pole 60 Hz SYN.3600 OP.3450 50 Hz SYN.3000 OP.2850 25 Hz SYN.1500 OP.1450 Most motors have a running winding and a starting winding.These windings are mounted on the stator. During starting,current goes through both windings when the motor reaches 60 to 75 percent of its running speed,the starting winding circuit is opened and the motor operates on running windings only.I hope this info. has been helpful.