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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Semi-conductor Question
Many years ago (possibly 50) you could buy a module that would take
the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? (I think I sent for one thru Popular Science mag at the time) Thanks |
#2
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Semi-conductor Question
In article
, Bob Villa wrote: Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? (I think I sent for one thru Popular Science mag at the time) Thanks I don't know about a solid state version. But, there are electro-mechanical versions that are quite common on motors less than 1 hp. They control the input to the start winding with a current sensitive relay. When the motor is turned on the inrush current closes the circuit to the start winding. When the motor gets up to speed and the current drops to the run value the relay opens the circuit the the start winding. I believe Klixon made them. You might try and google them. CP |
#3
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Semi-conductor Question
I've seen 3-wire starters that were marked Solid State (triac, presumably),
as replacement parts for current-type start relays, typically for refrigeration compressor motors (fractional HP). Places like Johnstone, or other suppliers for HVAC service folks should have numerous models to choose from. You may need to know a motor's specs, at least the LRA locked rotor amps rating, to be able to make an informed selection of starter devices. The following is a post from rec.crafts.metalworking.. I bought a couple of used Dayton (1/3 HP) bench grinders recently, and found some Klixon current-type motor starter relays being used instead of centrifugal switches for switching between Start and Run windings in these small split-phase 120VAC induction motors. http://www.sensata.com/klixon/motor-protector-3cr.htm I mention these relays because they would be a suitable replacement for damaged mechanical components or switch contacts related to centrifugal switches. These relays are the types used with refrigeration and air conditioning compressors, and also completely suitable for other split-phase motors. They have a heavy duty winding that the motor current passes thru, not a separate coil like common relays. When the power is turned on, the relay is pulled in, to make contact to the Start winding. The starting amperage of the motor is initially high, but it drops as the rotor approaches Run speed, the relay drops out, connecting the line voltage to the Run winding. There are charts of different models of the SR start relays (in PDFs at the link above), but I didn't find any type of selector guide for choosing what the appropriate amp ratings would be for various HP ratings. The models of Klixon SRs I was looking at were applicable for motors up to 15A (3CR series), and the next larger series of SRs were for up to 25A, so these ratings would cover nearly all single phase split-phase motors (capacitor start or non-capacitor start) used in a home shop environment. One particular aspect of the SRs is that they are gravity-dependent, and therefore need to be installed with the proper end pointed up. Aside from that, they are highly reliable starting devices, rated for about 1 million cycles. The specific ratings used for a 1/3 HP bench grinder motor use an 11A pull-in (Start) spec and a 6A drop-out (Run) spec. Of course, larger motors would use higher rated specs for pull-in and drop-out currents, and the ratings vary in tenths-of-an-ampere (11.5A/6.3A, etc). -- Cheers, WB .............. "Bob Villa" wrote in message ... Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? (I think I sent for one thru Popular Science mag at the time) Thanks |
#4
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Semi-conductor Question
On Aug 21, 11:45*am, "Wild_Bill" wrote:
I've seen 3-wire starters that were marked Solid State (triac, presumably), as replacement parts for current-type start relays, typically for refrigeration compressor motors (fractional HP). Places like Johnstone, or other suppliers for HVAC service folks should have numerous models to choose from. You may need to know a motor's specs, at least the LRA locked rotor amps rating, to be able to make an informed selection of starter devices. The following is a post from rec.crafts.metalworking.. I bought a couple of used Dayton (1/3 HP) bench grinders recently, and found some Klixon current-type motor starter relays being used instead of centrifugal switches for switching between Start and Run windings in these small split-phase 120VAC induction motors.http://www.sensata.com/klixon/motor-protector-3cr.htm I mention these relays because they would be a suitable replacement for damaged mechanical components or switch contacts related to centrifugal switches. These relays are the types used with refrigeration and air conditioning compressors, and also completely suitable for other split-phase motors. They have a heavy duty winding that the motor current passes thru, not a separate coil like common relays. When the power is turned on, the relay is pulled in, to make contact to the Start winding. The starting amperage of the motor is initially high, but it drops as the rotor approaches Run speed, the relay drops out, connecting the line voltage to the Run winding. There are charts of different models of the SR start relays (in PDFs at the link above), but I didn't find any type of selector guide for choosing what the appropriate amp ratings would be for various HP ratings. The models of Klixon SRs I was looking at were applicable for motors up to 15A (3CR series), and the next larger series of SRs were for up to 25A, so these ratings would cover nearly all single phase split-phase motors (capacitor start or non-capacitor start) used in a home shop environment. One particular aspect of the SRs is that they are gravity-dependent, and therefore need to be installed with the proper end pointed up. Aside from that, they are highly reliable starting devices, rated for about 1 million cycles. The specific ratings used for a 1/3 HP bench grinder motor use an 11A pull-in (Start) spec and a 6A drop-out (Run) spec. Of course, larger motors would use higher rated specs for pull-in and drop-out currents, and the ratings vary in tenths-of-an-ampere (11.5A/6.3A, etc). -- Cheers, WB ............. "Bob Villa" wrote in message ... Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? *(I think I sent for one thru Popular Science mag at the time) Thanks This was a totally solid state device...like a timed triac that cuts- out after a half second. |
#5
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Semi-conductor Question
On Aug 20, 5:16*am, Bob Villa wrote:
Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? *(I think I sent for one thru Popular Science mag at the time) Thanks It is amazing to me that they aren't commonly available! |
#6
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Semi-conductor Question
On Mon, 23 Aug 2010 05:17:04 -0700, Bob Villa wrote:
On Aug 20, 5:16Â*am, Bob Villa wrote: Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? Â*(I think I sent for one thru Popular Science mag at the time) Thanks It is amazing to me that they aren't commonly available! Google --- PLC module. HTH -- Live Fast, Die Young and Leave a Pretty Corpse |
#7
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Semi-conductor Question
On Aug 23, 8:58*am, Meat Plow wrote:
On Mon, 23 Aug 2010 05:17:04 -0700, Bob Villa wrote: On Aug 20, 5:16*am, Bob Villa wrote: Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? *(I think I sent for one thru Popular Science mag at the time) Thanks It is amazing to me that they aren't commonly available! Google --- PLC module. HTH -- Live Fast, Die Young and Leave a Pretty Corpse Not even close. This was a small (a little larger than a postage stamp), simple device. I remember using one on a 5 HP motor that wouldn't start. It was for a bakery mixing machine. |
#8
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Semi-conductor Question
On Tue, 24 Aug 2010 06:28:50 -0700, Bob Villa wrote:
On Aug 23, 8:58Â*am, Meat Plow wrote: On Mon, 23 Aug 2010 05:17:04 -0700, Bob Villa wrote: On Aug 20, 5:16Â*am, Bob Villa wrote: Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? Â*(I think I sent for one thru Popular Science mag at the time) Thanks It is amazing to me that they aren't commonly available! Google --- PLC module. HTH -- Live Fast, Die Young and Leave a Pretty Corpse Not even close. This was a small (a little larger than a postage stamp), simple device. I remember using one on a 5 HP motor that wouldn't start. It was for a bakery mixing machine. Thermistor across the start cap? -- Live Fast, Die Young and Leave a Pretty Corpse |
#9
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Semi-conductor Question
"Meat Plow" wrote in message news On Tue, 24 Aug 2010 06:28:50 -0700, Bob Villa wrote: On Aug 23, 8:58 am, Meat Plow wrote: On Mon, 23 Aug 2010 05:17:04 -0700, Bob Villa wrote: On Aug 20, 5:16 am, Bob Villa wrote: Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? (I think I sent for one thru Popular Science mag at the time) Thanks It is amazing to me that they aren't commonly available! Google --- PLC module. HTH -- Live Fast, Die Young and Leave a Pretty Corpse Not even close. This was a small (a little larger than a postage stamp), simple device. I remember using one on a 5 HP motor that wouldn't start. It was for a bakery mixing machine. Thermistor across the start cap? Already suggested - he seems to be ignoring it. Murata make a range of motor start thermistors (posistor). By the look of the picture on the front of the catalogue they may be plug in replacements for existing start winding solenoids. |
#10
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Semi-conductor Question
On Tue, 24 Aug 2010 16:25:30 +0100, ian field wrote:
"Meat Plow" wrote in message news On Tue, 24 Aug 2010 06:28:50 -0700, Bob Villa wrote: On Aug 23, 8:58 am, Meat Plow wrote: On Mon, 23 Aug 2010 05:17:04 -0700, Bob Villa wrote: On Aug 20, 5:16 am, Bob Villa wrote: Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? (I think I sent for one thru Popular Science mag at the time) Thanks It is amazing to me that they aren't commonly available! Google --- PLC module. HTH -- Live Fast, Die Young and Leave a Pretty Corpse Not even close. This was a small (a little larger than a postage stamp), simple device. I remember using one on a 5 HP motor that wouldn't start. It was for a bakery mixing machine. Thermistor across the start cap? Already suggested - he seems to be ignoring it. Murata make a range of motor start thermistors (posistor). By the look of the picture on the front of the catalogue they may be plug in replacements for existing start winding solenoids. Back in my youth I went to school for HVAC and got a job with a family owned company who installed Trane. I can remember installing hard start kits. But my specialty was gas fired ammonia systems. Quite a few residential and small office units around. Mostly 5 ton. Hell natural gas was cheap back then. Our local gas company went on strike and I was working on those things 24 hours a day it seemed. So freon-based systems were not part of my routine except for the then emerging residential heat pump units. But I do remember the solid state hard start kits. I think this Villa dood is somewhat purposefully dense. -- Live Fast, Die Young and Leave a Pretty Corpse |
#11
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Semi-conductor Question
On Aug 24, 8:25*am, "ian field"
wrote: "Meat Plow" wrote in message news On Tue, 24 Aug 2010 06:28:50 -0700, Bob Villa wrote: On Aug 23, 8:58 am, Meat Plow wrote: On Mon, 23 Aug 2010 05:17:04 -0700, Bob Villa wrote: On Aug 20, 5:16 am, Bob Villa wrote: Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? (I think I sent for one thru Popular Science mag at the time) Thanks It is amazing to me that they aren't commonly available! Google --- PLC module. HTH -- Live Fast, Die Young and Leave a Pretty Corpse Not even close. *This was a small (a little larger than a postage stamp), simple device. *I remember using one on a 5 HP motor that wouldn't start. *It was for a bakery mixing machine. Thermistor across the start cap? Already suggested - he seems to be ignoring it. Murata make a range of motor start thermistors (posistor). By the look of the picture on the front of the catalogue they may be plug in replacements for existing start winding solenoids. There is no starting cap...it would take the place of a centrifugal opening starting switch. I'll Google posistor and see where that leads. (thanks meathead for the comment-helpful indeed) |
#12
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Semi-conductor Question
On Tue, 24 Aug 2010 09:27:51 -0700, Bob Villa wrote:
On Aug 24, 8:25Â*am, "ian field" wrote: "Meat Plow" wrote in message news On Tue, 24 Aug 2010 06:28:50 -0700, Bob Villa wrote: On Aug 23, 8:58 am, Meat Plow wrote: On Mon, 23 Aug 2010 05:17:04 -0700, Bob Villa wrote: On Aug 20, 5:16 am, Bob Villa wrote: Many years ago (possibly 50) you could buy a module that would take the place of a starting relay or centrifugal cut-out for an AC motor. Where do you find them? (I think I sent for one thru Popular Science mag at the time) Thanks It is amazing to me that they aren't commonly available! Google --- PLC module. HTH -- Live Fast, Die Young and Leave a Pretty Corpse Not even close. Â*This was a small (a little larger than a postage stamp), simple device. Â*I remember using one on a 5 HP motor that wouldn't start. Â*It was for a bakery mixing machine. Thermistor across the start cap? Already suggested - he seems to be ignoring it. Murata make a range of motor start thermistors (posistor). By the look of the picture on the front of the catalogue they may be plug in replacements for existing start winding solenoids. There is no starting cap...it would take the place of a centrifugal opening starting switch. I'll Google posistor and see where that leads. (thanks meathead for the comment-helpful indeed) Never got into actual motor repair except for taking apart 10/15 horse 230 volt single phase repulsion/induction motors, then having the rotor/ stator rewound, the com resurfaced or replaced. Other than that was a simple plugin solid state replacement for a three pin residential AC compressor. There were direct replacements or hard start replacements to give the compressor a month or so longer useful life while the owner scraped up the cash for a replacement. -- Live Fast, Die Young and Leave a Pretty Corpse |
#13
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Semi-conductor Question
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#14
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Semi-conductor Question
On Tue, 24 Aug 2010 17:40:18 +0100, ian field wrote:
http://www.murata.com/products/catal...k99e_l0725.pdf Yeah I mistyped PLC for PTC a couple replies ago. Google --- PLC module. Still that doesn't replace a centrifugal clutch directly although you could probably jury-rig one. -- Live Fast, Die Young and Leave a Pretty Corpse |
#15
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Semi-conductor Question
"Meat Plow" wrote in message news On Tue, 24 Aug 2010 17:40:18 +0100, ian field wrote: http://www.murata.com/products/catal...k99e_l0725.pdf Yeah I mistyped PLC for PTC a couple replies ago. Google --- PLC module. Still that doesn't replace a centrifugal clutch directly although you could probably jury-rig one. "clutch"?! |
#16
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Semi-conductor Question
On Tue, 24 Aug 2010 18:06:52 +0100, ian field wrote:
"Meat Plow" wrote in message news On Tue, 24 Aug 2010 17:40:18 +0100, ian field wrote: http://www.murata.com/products/catal...k99e_l0725.pdf Yeah I mistyped PLC for PTC a couple replies ago. Google --- PLC module. Still that doesn't replace a centrifugal clutch directly although you could probably jury-rig one. "clutch"?! Well yeah a clutch, switch, kickout what the **** ever you want to cal it. -- Live Fast, Die Young and Leave a Pretty Corpse |
#17
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Semi-conductor Question
On Aug 24, 9:40*am, "ian field"
wrote: http://www.murata.com/products/catal...k99e_l0725.pdf I went to an electrician and this is what I got... http://stearns.rexnord.com/products/Cat_902_table.asp Thanks for the help guys! |
#18
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Semi-conductor-Answer
On Aug 24, 1:47*pm, Bob Villa wrote:
On Aug 24, 9:40*am, "ian field" wrote: http://www.murata.com/products/catal...k99e_l0725.pdf I went to an electrician and this is what I got... http://stearns.rexnord.com/products/Cat_902_table.asp Thanks for the help guys! |
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