Power Consumption Comparison : Clutch vs Servo sewing setup

[baileyuph]

It has been stated many times that a machine with servo setup consumes less power
than a clutch arrangement.

Could someone reference a technical document/study on this issue.  It would be interesting reading as well as understanding.  This question was put to a sewing vendor and the answer was :  " they, the entity supplying such, says the servo consumes less".  The vendor didn't go to the risk of supporting a savings.

There is an engineering study, I googled, which provided a very technical discussion of servo and provided a very clear understanding of servo engineering/usage of servo engineering in auto assembly welding operations (they use servos) that led one to understand cost isn't an advantage, it was the precision that could be achieved with servo in placement of spot welds.  That study did go so far as to suggest that power consumption is increased with servos because most power is consumed during starts, something the assembly lines do endlessly.  That made sense because each start up the energy consumed has to increase to over come the inertia Resistance of the motor.  Once a clutch is started, that consumption is over, not true with a servo.  The engineering article I am alluding to was very technical, I understood enough of what was being said to merely ask this question.

The follow on question is;  If one knows of a statistical study -  that has been published - that gives the magnitude of savings in energy that can be derived from a servo vs a clutch motor, it would certainly educate a dummy like me.  It can't be significant, even if true, because my electric bills, obviously with clutch motors, aren't really significant anyway.  This isn't an argument either way, the significance of the argument is the issue of magnitude of the comparison.  If I saved all electric cost (with servo), It couldn't be that much because most electric consumption around the shop is definitely the AC requirements.  Anyone noticed that to be true lately? ;)  Little sense of humor here.

Any technical documents of reference to the subject, here would or could be interesting reading.  An engineer, with strong theoretical understanding of electric motors, servos, would readily understand this question.  Not a salesman or some backyard user of the equipment.

Doyle

[Mojo]

Doyle:

I have never been able to find any documentation to back up the theory that servos save money. I do believe we had a member on here who switched from clutch to servo motors and they seen a difference in their electric bill but for the life of me I cannot remember who it was.

I would be interested to hear from Bob Kovar or Greg on this issue. Surely they have had some large customers who have switched and reported back to them any savings they may have seen.

I still believe that the clutch/servo debate hinges more on operator preference versus savings. I know with me I prefer a servo and found that sewing with a clutch motor was frustrating for me. But then I have always sewed with a servo and my one experience sewing with a clutch motor was a bad one. There are many out there who have sewn with nothing but a clutch motor and do not like servos. 6 one way - half a dozen the other. :)

But like you I would be interested in knowing if there is a savings and if so how much ?

Chris

[sofadoc]

I do believe we had a member on here who switched from clutch to servo motors and they seen a difference in their electric bill but for the life of me I cannot remember who it was.

That was probably me. But there were extenuating circumstances.
My local electric company charges a "demand fee" if your consumption reaches a certain point. Once you reach that point, you pay an extra $75 a month for the rest of the calender year. After installing the servo motor, my consumption dropped just below that point (I was teetering right on the edge). So these results wouldn't be typical for anyone else. Since then, I have installed a new AC unit that keeps me well below the "demand fee" point. But all things being equal, I doubt that the difference in energy consumption for most people would be noticeable.

[MinUph]

I don't know any tests that have been done but I sew on both servo and clutch. I had a clutch for 30 years and my new machine is a servo. I still sew with a clutch at my day job. If I were to have a preference I would go with the Servo. It would seem to save $$ but that is secondary. The motor doesn't run until you press on the pedal. Leaving it on is less noisy and I would think it would save money but it is not the reason I like them. They are also very speed adjustable where a clutch is not. Not a big deal once your use to a machine but nice while you do. When at work we tend to turn off the machine when not in use. At home I leave it on for the day when sewing or not.

[Mojo]

Paul:

I should have video taped me using a clutch motor. It would have given everyone a great laugh. :)

I knew it was a matter of time before I ran my finger through my machine. I must be a half wit or something but I was never able to get used to a clutch motor. I have lost a lot of feeling in my feet over the last couple years due to the toxicity of the chemo drugs which is why I sew with slippers on. Maybe that is what caused my problems with a clutch motor.

The constant humming of the clutch motor drove me nuts too. :)

Chris

[Toledo Mach. Sales]

We have some Amish customers that are able to use batteries & invertors for power now & use 110 volt motors.They found out the clutchmotors drain their batteries quicker than the D.C.Servo which is what they are now buying.
Bob

[SHHR]

Ok, since Bob said it, I saw am Amish man driving a truck through town the other day and looked scared out of his wits (no it wasnt pulled by horses either) and my daughter just attended a church summer camp that has several Amish farms located around it and many of them now have solar panels on the house and barn roofs.
Kyle

[gene]

It must be hot and humid in heaven. God figured that if he is going to use some AC up there, might as well have the followers down here enjoy a bit of the benefits from the free flow of electrons.

gene

[Mojo]

Bob has explained to me about some of the sewing machine setups he has encountered on the Amish farms. He has a rather large Amish clientele so has seen some pretty amazing setups.

I was amazed at how some of them work using these machines " off the grid ". Sewing by candle light or battery light, etc. and the way they power their machines is amazing in itself.

I am not an Amish expert but I do know their religion requires they avoid ownership of certain things - vehicles, electricity, etc. But many of these craftsmen work for other companies and have no problem using electricity at factories. If you head down to Indiana and check out some of the RV factories you will find Amish craftsmen inside making cabinets, etc. using electricity and electrical tools.

I believe their religious beliefs prevent them from owning them or having electricity to their houses. Yet for some strange reason they can use batteries and solar cells and inverters. Hmmmm....

Chris

[sofadoc]

I believe their religious beliefs prevent them from owning them or having electricity to their houses. Yet for some strange reason they can use batteries and solar cells and inverters. Hmmmm....

Reminds me of a local church. The youth minister wanted to bring in some guitars and amps for some more "contemporary" Christian music. He was quickly told that such high-tech equipment was against their religious beliefs.

But they were OK with the really big badass AC unit out back. ;)

[gene]

Amish Christmas tree lights

http://www.youtube.com/watch?v=M8tsCYyH3TU


When my son was young we would go down to Mammoth Cave in southern Kentucky the Friday before Christmas. They would light the walk into the main cavern with candles and would have a big Christmas tree with candles on it in the main cavern. The guides would sling a lit rag with oil on it up onto the ledges so the sides of the cavern could be seen. This was first done in the late 1800s.

The best year was when they had a hand bell choir play Christmas songs.

gene

[Toledo Mach. Sales]

The thing about electricity is they are not supposed to be tied in with the outside world.These traditions are different in different communities now as the elders make the rules to suit them.(about like our president)Some areas allow electric by generators & then some are now wired like we are while some use batteries & some have to use gas lights or kerosene.It works the same w/phones some can only have cell phones,some have to have the phone by the road & others have them in their shop.The funniest thing is tractors some are not allowed to have air tires so they make special rims out of flat steel & take a tractor tire & cut the sidewall off & bolt them on the flat steel.The some still have to use horses in the field.
Bob

[Judy_Boat]

kinda back to topic

Basicially the clutch and the servo motors have the same type of electric motor at their hearts.
What is different is the type of control over the motor spin(speed). A servo can be controlled in many smaller steps, the clutch type just rips up to speed.
Electrically, you find that the clutch motor can spike up to 14 amps on startup. We put an ammeter on my machine and checked this.
The servo motor will not have the same high spike. (If your electric utility monitors a peak usage value, at any point, this could cause high prices. But this is not normally seen domestically)

Once the systems are running (steady state) electric consumption should be the same.

Basically it is the mechanical kind of control you want over your sewing machine that will guide your choice of motor.

[baileyuph]

The servo motor will not have the same high spike.

Judy, if I understand correctly, you are saying the servo motor will not spike up on amperage unless the sewing task (something heavy) demanded it?

I appreciate your general conclusion, little difference in power consumption. 

You say same motor for both.  Servo only runs on stitch demand.  Clutch runs until motor is turned off. 

Now my question:  If clutch is on, all the time, then the spike up in stitch consumption only happens when the motor is starting up, over comes inertia?  Correct?  Then, the clutch motor might not be as expensive to run if it is being compared to a servo motor, constantly starting up doing heavy stitching?

Simple point being made, servo is overcoming inertia more frequently, the time spike up is expected.

If I get some time, maybe reading some more engineering studies on this issue would be of interest.  At least it might contribute to understanding.

On a different thought, the preference point you made, there is some detailed type of stitching that justifies a servo.  The intricate type of stitching, especially decorative.

Doyle

[Mojo]

I still would have to say that if the servo and clutch motors were comparable in electrical usage then the Amish would not being cleaning Bob Kovar out of servos.

As he stated they are all going to servo's because their batteries last longer versus running clutch motors.

In my younger years I worked for a power company. For a brief stint I worked on power lines. I can remember doing power banks ( 220/440 ) and all kinds of phasing ( delta and Y phasing ). Did you know that a commercial building while having 440 power banks feeding their buildings for electric also can have 220 power banks for their lighting ? The higher the voltage the more efficient electricity flows. This is one of the reasons why many countries do not have 110 voltage services. It is much cheaper to get electricity to your house via 220 lines then 110.

Most commercial/industrial properties use 220 and 440. Industrial motors are also phased
( XYZ ). You can reverse rotate an industrial 220 or 440 motor by simply swapping the hot leads. Electricity is a weird thing. :)

Consider the law that Florida enacted two or three years ago. No pool motors over 1 hp can be sold here anymore unless they are the high efficiency motors. They look identical to the older motors but some will save over $ 1,000 a year on electrical costs. Most of this savings comes in reduction gearing and electronics.

I would be interested to know what your research digs up Doyle. I am going to guess though that the servo will come out on top in the way of efficiency and electrical usage.

Chris