Singer 15-91 power

[Burkhardt]

Does a machine like that draw power plugged in or only when it's being used?

[Constabulary]

We do not know how your machine is set up and if you have a circuit breaker on your machine or not. No matter what when you leave an (especially older) electric deceive plugged in I would recommend a circuit breaker or a power strip equipped with one.

[Northmount]

13 hours ago, Burkhardt said:

Does a machine like that draw power plugged in or only when it's being used?

What motor and controls are on it?

[Burkhardt]

1 hour ago, Northmount said:

What motor and controls are on it?

What ever was originally on it from new 60-70 years ago. I think it's a pot or potted(?) motor and foot pedal.

 

10 hours ago, Constabulary said:

We do not know how your machine is set up and if you have a circuit breaker on your machine or not. No matter what when you leave an (especially older) electric deceive plugged in I would recommend a circuit breaker or a power strip equipped with one.

  To use to turn on and off or for general protection for machine?

[Northmount]

6 minutes ago, Burkhardt said:

What ever was originally on it from new 60-70 years ago. I think it's a pot or potted(?) motor and foot pedal.

Pictures?? 

Doesn't sound like a clutch motor and by age definitely not a servo.  So no, the motor doesn't draw any current if just plugged in but not running.  Unless ... there is a short circuit or a build up of somewhat conductive material between hot and neutral connections.  If someone has added a 3rd wire safety ground to the system and there could be some leakage from the motor windings to the grounded frame assuming the foot control was placed on the neutral side rather than the hot side of the line.  Had a Sunbeam Mixmaster that gave you a zing if you touched it and the kitchen sink at the same time.

[Burkhardt]

6 minutes ago, Northmount said:

Pictures?? 

Doesn't sound like a clutch motor and by age definitely not a servo.  So no, the motor doesn't draw any current if just plugged in but not running.  Unless ... there is a short circuit or a build up of somewhat conductive material between hot and neutral connections.  If someone has added a 3rd wire safety ground to the system and there could be some leakage from the motor windings to the grounded frame assuming the foot control was placed on the neutral side rather than the hot side of the line.  Had a Sunbeam Mixmaster that gave you a zing if you touched it and the kitchen sink at the same time.

Not mine but it's identical to this.

[Wizcrafts]

The Singer 15-91 is a domestic/home sewing machine; not industrial. It is definitely not a leather sewing machine! That's what's causing the confusion in the answers. I have owned a couple of them. I rebuilt and sold them in my leather and sewing shop as a sideline. I even wrote a web page devoted to the Singer 15-91.

Now, as for the motor, it is a pod motor built into the head. These motors are old now and the wires and brushes wear out over time. You can replace the brushes yourself if the motor sparks when it runs. But, rewiring it is probably not worth the trouble. You are better off trying to buy a rebuilt pod motor online. As it is, it may draw power when not is use. So, unplug it it until you intend to sew. Plug it into a power bar with a breaker, in case the old motor decides to short out. Beware, you could become part of the AC circuit!

Because of the way the 15-91 (and model 201) was designed, it is not practical to try running it on an external motor. If it runs erratically, or not at all, get rid of it or buy a rebuilt motor. You'll have to unplug it and carefully detach the old wires, then attach the new ones.

[Burkhardt]

9 minutes ago, Wizcrafts said:

The Singer 15-91 is a domestic/home sewing machine; not industrial. It is definitely not a leather sewing machine! That's what's causing the confusion in the answers. I have owned a couple of them. I rebuilt and sold them in my leather and sewing shop as a sideline. I even wrote a web page devoted to the Singer 15-91.

Now, as for the motor, it is a pod motor built into the head. These motors are old now and the wires and brushes wear out over time. You can replace the brushes yourself if the motor sparks when it runs. But, rewiring it is probably not worth the trouble. You are better off trying to buy a rebuilt pod motor online. As it is, it may draw power when not is use. So, unplug it it until you intend to sew. Plug it into a power bar with a breaker, in case the old motor decides to short out. Beware, you could become part of the AC circuit!

Because of the way the 15-91 (and model 201) was designed, it is not practical to try running it on an external motor. If it runs erratically, or not at all, get rid of it or buy a rebuilt motor. You'll have to unplug it and carefully detach the old wires, then attach the new ones.

I probably didn't put in right section. It's ten times the machine compared to the new garbage plastic ones. This one works great on thinner stuff like wallet interiors or canvas bags. It did not like 138 to much and on certain things was OK but definitely likes 92 thread much better. Thanks Wiz 

[Ole South]

The 15-91's (aka Farmer's Wife's Friend) I've rebuilt are way more forgiving on the thread being used than the 201's and will do better on thin leather and canvas.  That being said, on fabric you cannot beat a 201 for consistent stitch quality (Top and Bottom stitch!!), plus 201's are much quieter... no clack-clack.  A lot of alteration shops started with 201's back in the day until they could afford a commercial Singer, Juki ect.  Zig-zag was accomplished via a mechanical attachment that moved the fabric rather than the needle (same attachment worked/works for most straight shaft black Singers).  We still use a 15-91 or 201 with a Singer Buttonholer Attachment (from the 40's) just for the button holes on shirts and garments.  More options, better looking buttonholes.

138 sometimes will work (cosmetically) on the 15-91 depending on the material, if bobbin is threaded with 66 or lighter and you use the largest needle you can find that fits, usually this is a size 18, tho 19 would be better.  Don't try this with "Coat and Button" thread in the bobbin... the stuff we get these days tagged as Coat and Button runs very inconsistent thru-out the spool.

But...  these machines are sooo NOT a substitute for an industrial walking foot for general leather work.  

Edited November 2, 2022 by Ole South
double negative

[Wyowally]

A 15-91 is a sought-after machine by the vintage Singer people with good reason. The direct drive motor is powerful. Instructions for complete motor rebuilds are out there for those who want to take it on.

The question was does it draw power when just sitting there plugged in - no, it shouldn't, just like most other domestic pedal controlled machines. It COULD if there is a problem with the pedal, cords, or the light or motor wiring. If it does, I would suspect the pedal first. Power doesn't get to the motor except through the pedal. The way Singer designed their connectors makes it challenging to rewire and get correct, and you never know if Bubba worked on it and screwed something up. 

[CowboyBob]

I used to work for an ex-Singer salesman & he told me when they demonstrated them they would sew through a wooden yardstick to impress people with the power.They were such a good machine that when they started selling the newer Touch & Sews (with plastic gears that break) they took them in on trade, then out in the alley & busted them up w/a sledge to get them off the market.

[Ole South]

Re: Drawing power when idle:

One of the early to mid-20th century foot pedals were a stacked carbon disk controlled device, I've often seen these on the 15-91s.  So yes, the potential for any cast iron (black) Singer drawing power when unused is present.

How they work (ie: WHY they may still pass current when idle)
Rather than a rheostat/variable potentiometer or variable transformer, these use a stack (or most often dual stacks) of carbon disks working as a pressure resistor.  The individual disks are slightly thicker but about the diameter of a dime.  Pressure is offset/removed by a spring (think return to zero pressure) and as you press the foot pedal down the stack of carbon disks are compressed reducing resistance and thus increasing current flow in a fairly linear manner.  Since these motors were AC/DC capable (I believe down to about 50vdc) this was an effective and inexpensive control solution for either power source.   Effectively, the tighter the disks are pressed together the more juice flows.  Even so, there was no insulation or air gap created between the disks when the spring returned the pedal thus eliminating the possibility of Zero current (yes, this is a double negative).  

Usually over the years the spring(s) would weaken, and dust (both carbon and common household) would build up between the disks reducing its efficiency by not allowing current flow which was the most common reason for replacement.  BUT... I have seen these as the apparent precipitating failure* causing the wires exiting the Bakelite power connection (to motor) fry in a rare case or two.  Probably why my Grandmother never converted her Red Eye model 66 from treadle to motor. 

Rewiring these machines is not impossible as most of the Bakelite connectors were threaded brass thru-hole posts with screws forming the connection... better than the "wind around the screw" we see today imo.  If you take this path (re-wiring): current flow to a vintage motor is/was, on the average, .75 amp at 120vac.  Modern replacement motors are more in the range of 1.0 to 1.5amp @ 120vac.  Original wiring was typically cotton or treated linen covered rubber which is prone to cracking and fraying over time.  Choose your replacement wire accordingly (I.e. for the motor used)

So yeah.... if you are using a vintage machine and foot pedal I'd err on the side of safety and unplug the bugger. (or at least switch off the surge suppressor/extension cord it's plugged into and you never know then a grandkid is gonna explore under the sewing table.)

 

* Burnt open wiring and evidence of severe arcing between the carbon disks. Sometimes holes were blown completely through adjacent carbon disks or they were vaporized all together.

Edited November 2, 2022 by Ole South