Looking for a low speed start servo

[chrisash]

To go with my new (ish) 111, i am looking for advice on a new servo which will give me slow speed without a reducer and the power to get through say 2 x 3mm veg tan which is about average for what i do

I bow to your experiences

thanks

[Constabulary]

Most "cheap" servos start at 200-300 rpm and have a 70mm pulley. To slow down the motor far enough you may install a larger hand wheel instead of a speed reducer. I do not know of any "cheap" (meaning 100-200€ / GBP range) servo motor in the EU hemisphere that is extremely slow at the start and has a good amount of torque at slow speed. Not saying there is none but I do not know of any. The addition of a 40-50mm motor pulley + a larger hand wheel or a speed reducer is almost mandatory I´d say. I don't want to got without a SR - I have them on all my machines. Much more comfortable!

Maybe the HoShing series is what you need but I have no experience with them.

https://globalsew.com/ho-hsing/

Edited November 7, 2020 by Constabulary

[Wizcrafts]

My Family Sew FL-550s with a 50mm pulley meets that description. However, a lot depends on the diameter of the machine pulley. I use this motor on several machines and it has the most low speed torque on machines with larger top pulleys. The others need a speed reducer. I would say that if your machine has at least a 4" pulley you will be good to go with just this motor and its 50mm pulley.

In the event this exact motor isn't available where you are at, try to find a Consew equivalent and buy a 50mm pulley that fits its shaft (I think it is close to 5/8 inch, or a metric equivalent). Just make sure the motor has brushes and a knob to control the speed.

[Gymnast]

3 hours ago, Wizcrafts said:

My Family Sew FL-550s with a 50mm pulley meets that description.

I got no daubt that this is a good motor to use. But I am a bit puzzled by the specifications in the link:

110 volts AC, 550 Watts

3/4 HP output

3/4 HP output is the same as the same as 552 W shaft power. It is actually a bit more than the specificed input electrical power to the drive. I know something about this size of motors, and my estimate would be an effiency of about 60 % at max power output. So something is wrong with these figures. Perhaps the the specified shaft power is less or the specified input power is higher. If the motor provide 552 W shaft power at 60 % motor and drive efficiency, the input power should be 920 W.

Edited November 7, 2020 by Gymnast

[Pintodeluxe]

Motor HP claims are notoriously incorrect.  Just call it a 550 watt and use that to compare one model of servo to another.

I second the Family 550 servo (aka New Tech, Rex, Consew).  I use them with and without reducers.  Approaching 20oz of total leather sewn, the reducer is nice.  But with lighter / thinner leather than that, the reducer probably isn't necessary.  

Best of luck with it. 

[Constabulary]

yes but afaik the Family sew motors are not available on our sides of the pond (meaning EU and UK) and in 230V but I may be wrong.

[dikman]

The "generic" push-button servos work well with a small motor pulley and either a reducer or large pulley to replace the handwheel.  I know you said you don't want to fit a reducer, Chris, but you may not have any choice in order to achieve what you want.

[Gymnast]

2 hours ago, Constabulary said:

yes but afaik the Family sew motors are not available on our sides of the pond (meaning EU and UK) and in 230V but I may be wrong.

I just looked at motors from some suppliers in Europe, and I agree that it is hard to find the brushed DC motors. Almost all servo motors sold in Europe seems to be of the brushless type. I found one supplier in the UK via ebay with a brushed DC motor:

https://www.ebay.co.uk/itm/Industrial-Sewing-Machine-Servo-Motor-Mains-240v-with-On-Off-switch-Fittings-/263472630087 

I guess it will work like the Family motor Wizcrafts suggested.

If you go for a brushless servo motor, as it seems most users do in Europe, then look for a motor with a minimum speed at 100 RPM. Most motors got a minimum speed at 200 RPM or even 500 RPM. Do not trust a specifications that say 0 RPM to 4500 RPM. It do have a minimum speed higher than zero. This is one brushless motor sold in Europe, with a minimum speed of 100 RPM:

https://www.sewtex.de/Motore--Gestell--Tischplatte--Zubehoer-fuer-Naehmaschinen--Stuehle--Leuchten--Transportwagen--Industriestuhl--Schere/ZOJE-TZ-ZJ550W-S-Servomotor--Naehmaschinenmotor.html 

I guess you can find a supplier for that in UK as well. I never used a Zoje servo motor, but I have seen a few good reviews.

Edited November 8, 2020 by Gymnast

[Constabulary]

1 hour ago, Gymnast said:

just looked at motors from some suppliers in Europe, and I agree that it is hard to find the brushed DC motors. Almost all servo motors sold in Europe seems to be of the brushless type. I found one supplier in the UK via ebay with a brushed DC motor:

https://www.ebay.co.uk/itm/Industrial-Sewing-Machine-Servo-Motor-Mains-240v-with-On-Off-switch-Fittings-/263472630087 

I guess it will work like the Family motor Wizcrafts suggested.

Look at that - so I better shut up 

But 0 is off, right? And next step is 350 or is there an acceleration ramp between 0 and 350 when the knob is on 0?

Edited November 8, 2020 by Constabulary

[chrisash]

Looking at the Jack 513A does anyone have any knowledge of it

See it comes in 550 watt and 750 watt with only £20 difference in price

750 watt has top speed of 3500 compared to 550 at 4500 so does this mean  a probable lower starting speed i.e. 100 rather than 200rpm

Can you overpower machine in normal use

Be nice if we had a section on servo motors and what people thought of their model for use on leather