brightspark
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the trouble is with modern motors there on there limit . they may develope 3hp but an older larger motor has a better starting capacity
- Thread starter alfapat
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I have experienced problems with two of mine in really cold weather, the little wolf direct drive one I have had to warm up the cyl a bit with a heat gun before starting but once its running will be OK for the rest of the day. Another one is my big old aerostyle with a 4HP Cap start induction run motor which has an oil pump feeding the compressor I have to spin it by hand a few revs before switching on and then it dims the lights and kicks into life. The motors naturally take more power to start in cold weather because everything is tighter and oil is thicker, just look how many battery's and starter motors fail this time of year.
Agreed on the car issue, but thats quite different. Generally 4 or more cylinders, high compression immediately, lots more drag, etc. As I mentioned, I've turned quite a few pumps by hand without the motor attached and the effort is minimal even when cold.
If the motor struggles or draws excess current causing a trip there has to be a fault IMHO.
If the motor struggles or draws excess current causing a trip there has to be a fault IMHO.
definitely agree that the pump will be harder to turn when cold or in cold weather which will cause the motor to struggle more.
to work through this methodically, slip the belt off and note how it starts without load (stone cold). refit the belt and disconnect the outlet pipe from the pump head and see if it still runs fine (again, cold as possible).
let us know what you find.
to work through this methodically, slip the belt off and note how it starts without load (stone cold). refit the belt and disconnect the outlet pipe from the pump head and see if it still runs fine (again, cold as possible).
let us know what you find.
Not in my experience, well more resistance maybe but not MUCH more.
I'm working on the T30 Ingersoll I have at the moment, the pump has been removed and is on the bench. This is a big old pump and no lie, the pulley can be turned with one finger ! Obviously when it's upto speed and working against load the motor will work hard to turn it, but starting with an unloaded tank pressure feed would be nothing to the motor.
the snooper
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yes you can turn the pumps easy by hand as there is no load but when connected to a motor within a split second there is load even with an empty tank and the added resistance created by the temperature would seem to be enough to cause this problem.
as you mention in your post tigler your experience seems to be in conflit with a lot of people. if you google the subject you will find the problem is very common.
also does anyone have a manual for their machine giving operating temps i'll dig mine out and have a look
as you mention in your post tigler your experience seems to be in conflit with a lot of people. if you google the subject you will find the problem is very common.
also does anyone have a manual for their machine giving operating temps i'll dig mine out and have a look
brightspark
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motor current test
on my twin pump compressor i tested both motors there both 3hp .ones new and the others 8 years old . at 2c temperature the starting load on the new motor was 55.4 amp cold and 53.2amp warm on an empty tank the old motor started at 72.3 amp cold and 66 amp warm . starting under load warm old motor 66amp and new motor 52 amp . the full load running amps were old motor 13.2 amp and the new one 10.9amp . i would asume lower than freezing the readings would be s lightly higher and given that machine motors havent any spare capacity for load it wont help .theres no voltage drop on the cables as ive a short 35mm armoured cable feeding the shed and close to the mains supply under road
on my twin pump compressor i tested both motors there both 3hp .ones new and the others 8 years old . at 2c temperature the starting load on the new motor was 55.4 amp cold and 53.2amp warm on an empty tank the old motor started at 72.3 amp cold and 66 amp warm . starting under load warm old motor 66amp and new motor 52 amp . the full load running amps were old motor 13.2 amp and the new one 10.9amp . i would asume lower than freezing the readings would be s lightly higher and given that machine motors havent any spare capacity for load it wont help .theres no voltage drop on the cables as ive a short 35mm armoured cable feeding the shed and close to the mains supply under road
the snooper
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that could also indicate that that will be the maximum draw of the motor even if you locked the shaft of the motor.
and as bs said there is no more capacity left in the motors which says to me that 3hp motors are only just borderline powerful enough to run the macines with a 1.2 amp difference on the newer motor
and as bs said there is no more capacity left in the motors which says to me that 3hp motors are only just borderline powerful enough to run the macines with a 1.2 amp difference on the newer motor
You might well be correct there, but to dismiss the fact that it could compound the problem as others have experienced is your prerogative.
A little maintenance wouldn't go amiss here I think, clean the non return valve, change the oil, and if it was me I would put a new start cap on as well whatever it shows up on the meter just because if the bleed resistor had melted/burnt it means its had some hammer and could fail soon anyway. This is if the OP hasn't done this already of course.
I agree cold could reveal a problem somewhere else, like a faulty motor or cap, but I just don't think it's the main problem. From recent experience I think I'm going to replace caps on a routine basis now, as running a motor long term with a defective cap can cause it damage even before the cap terminally fails. Modern caps just don't seem to be very durable. They have a running hour rating but inactive time is also an issue with the inferior materials now often used in their construction.
Cret
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Hi all - hope it's ok for me to join in on this one as I also have a Sealey with EXACTLY the same issue and it's driving me nuts as it is less than a year old and barely used!
Mine is an SAC1153B model (150L 3hp single phase).
I bought it new in April and had not used it more than say 3 or 4 tank fulls since new when this began happening a few months ago and I've been trying to sort it since then.
Ordinarily I would have obviously sent it back but being on the Isle of Man this means I have to get a pallet and securely package it all back up myself for transit by ferry etc etc, and is generally a ballache, so I've been trying to sort it myself.
Mine will start when the tank is empty, or when part filled and warm, but not other than this. It's infuriating that I had a £100 24L Cosmo compressor from about 10 years ago that still runs fine despite all manner of abuse but spend £550 on an 'upgrade' and it won't even run!!
Anyway - this is what I've tried on mine to narrow it down:
1) Electrician has checked and confirmed that the power source is fine.
2) Oil level and type is fine (5/w50 synthetic in accordance with the instruction manual)
3) Motor starts very easily if the belt is removed
4) Compressor pump is VERY easy to turn by hand (ie 1 finger will turn it with ease) when belt is removed.
5) Unloader appears to be working correctly. It hisses from startup when tank is empty up to about 20psi, then stops hissing. When compressor stops it hisses as the pressure is dumped from cylinder/tank feed line.
6) Have replaced the check valve/non return valve, where the air feeds into the tank, as I was convinced this was the fault, but this did not really help
7) When the tank is empty, the compressor will normally start just fine
8) Once it succeeds in running, it will tend to restart easily, ie when warm. If it starts and I allow it to part fill the tank it will typically allow me to stop and start again repeatedly without problems.
9) Ambient temperature of my garage where it lives was around 10C when I began checking all this out. Not especially cold by any standards!
10) "Occasionally", the compressor trips the main fuse that feeds it from the house supply board (16 amp fuse, but not specifically a motor type fuse).
When this happens, it trips the fuse the instant the compressor start switch is deployed, and the motor does not turn at all. Resetting the fuse then means a second attempt at starting will not trip the fuse, but depending on the pump temp/tank fill state etc will either start or stall the thermal breaker. No idea why it just decides to trip the fuse but my sparky says all is fine on the power feed.
11) Air filter is clean!
12) Unloader valve is clean inside and doesn't "seem" to stick (hard to know though.....)
Sparky is adamant that the capacitors and motor are fine. He states that if either were faulty it would exhibit problems starting even with the belt off since a 3hp motor needs the capacitors to start correctly whether under load or not.
To me, and others I've asked, the most common cause of compressor problems is a faulty unloader, and the symptoms seem to suggest this is the case, BUT it does appear to be doing its job. It does a "PTCCHHHHHHHH!!!!!" when you stop the compressor from the unloader, so I can't see how if its venting there could still be pressure causing it to struggle on startup?
I'm at a loss if I'm honest. I don't want to have to randomly start buying replacement parts or to pay the local compressor place to investigate and repair. It cost me £550 so if should bloody well work given its nearly new, but sending it back will be a right cafuffle since it means getting a pallet, taking a day off work for the courier etc etc.
A replacement "pressure valve" (unloader/control unit) from Sealey is £40 delivered so I'd rather not have to buy one as part of this guessing game as I can't really afford to:
http://www.ccw-tools.com/Sealey-Power-Tools/Compressors/Belt-Drive-Compressors/Belt-Drive-Compressor-Spares/Sealey-SAC7250360000---Pressure-Switch/p-4-103-306-1681-34616/
I do have a spare new one that I bought for my Cosmo and never fitted as it turned out not to be the fault so I'm off to inspect that now and see if it might be compatible. If it is then I'll try swapping it out. If that works then I will send the Sealey one to them and respectfully ask that they send me a replacement FOC!
Hope this is ok posting on someone elses' thread but I thought given it's apparently the exact same issue and same brand it might be useful for us both to combine info and ideas.
Cheers
Jim
Mine is an SAC1153B model (150L 3hp single phase).
I bought it new in April and had not used it more than say 3 or 4 tank fulls since new when this began happening a few months ago and I've been trying to sort it since then.
Ordinarily I would have obviously sent it back but being on the Isle of Man this means I have to get a pallet and securely package it all back up myself for transit by ferry etc etc, and is generally a ballache, so I've been trying to sort it myself.
Mine will start when the tank is empty, or when part filled and warm, but not other than this. It's infuriating that I had a £100 24L Cosmo compressor from about 10 years ago that still runs fine despite all manner of abuse but spend £550 on an 'upgrade' and it won't even run!!
Anyway - this is what I've tried on mine to narrow it down:
1) Electrician has checked and confirmed that the power source is fine.
2) Oil level and type is fine (5/w50 synthetic in accordance with the instruction manual)
3) Motor starts very easily if the belt is removed
4) Compressor pump is VERY easy to turn by hand (ie 1 finger will turn it with ease) when belt is removed.
5) Unloader appears to be working correctly. It hisses from startup when tank is empty up to about 20psi, then stops hissing. When compressor stops it hisses as the pressure is dumped from cylinder/tank feed line.
6) Have replaced the check valve/non return valve, where the air feeds into the tank, as I was convinced this was the fault, but this did not really help
7) When the tank is empty, the compressor will normally start just fine
8) Once it succeeds in running, it will tend to restart easily, ie when warm. If it starts and I allow it to part fill the tank it will typically allow me to stop and start again repeatedly without problems.
9) Ambient temperature of my garage where it lives was around 10C when I began checking all this out. Not especially cold by any standards!
10) "Occasionally", the compressor trips the main fuse that feeds it from the house supply board (16 amp fuse, but not specifically a motor type fuse).
When this happens, it trips the fuse the instant the compressor start switch is deployed, and the motor does not turn at all. Resetting the fuse then means a second attempt at starting will not trip the fuse, but depending on the pump temp/tank fill state etc will either start or stall the thermal breaker. No idea why it just decides to trip the fuse but my sparky says all is fine on the power feed.
11) Air filter is clean!
12) Unloader valve is clean inside and doesn't "seem" to stick (hard to know though.....)
Sparky is adamant that the capacitors and motor are fine. He states that if either were faulty it would exhibit problems starting even with the belt off since a 3hp motor needs the capacitors to start correctly whether under load or not.
To me, and others I've asked, the most common cause of compressor problems is a faulty unloader, and the symptoms seem to suggest this is the case, BUT it does appear to be doing its job. It does a "PTCCHHHHHHHH!!!!!" when you stop the compressor from the unloader, so I can't see how if its venting there could still be pressure causing it to struggle on startup?
I'm at a loss if I'm honest. I don't want to have to randomly start buying replacement parts or to pay the local compressor place to investigate and repair. It cost me £550 so if should bloody well work given its nearly new, but sending it back will be a right cafuffle since it means getting a pallet, taking a day off work for the courier etc etc.
A replacement "pressure valve" (unloader/control unit) from Sealey is £40 delivered so I'd rather not have to buy one as part of this guessing game as I can't really afford to:
http://www.ccw-tools.com/Sealey-Power-Tools/Compressors/Belt-Drive-Compressors/Belt-Drive-Compressor-Spares/Sealey-SAC7250360000---Pressure-Switch/p-4-103-306-1681-34616/
I do have a spare new one that I bought for my Cosmo and never fitted as it turned out not to be the fault so I'm off to inspect that now and see if it might be compatible. If it is then I'll try swapping it out. If that works then I will send the Sealey one to them and respectfully ask that they send me a replacement FOC!
Hope this is ok posting on someone elses' thread but I thought given it's apparently the exact same issue and same brand it might be useful for us both to combine info and ideas.
Cheers
Jim
Seeing that you have only used it 3 or 4 times, have you tried "running it in" so to speak, tap open let it run for half an hour or so,let it cool and repeat do this for a few days see if it makes a difference. Does your motor have a start and run capacitor fitted if it does check that the run cap is ok.
brightspark
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all i can say is if the 16 amp breaker in the house is a b type change it to a c type to give a larger starting current and if comp is cold open the outlet and run empty for 10 mins to warm the oil in the comp then close the outlet and run up to pressure warm that will answer the questionHi all - hope it's ok for me to join in on this one as I also have a Sealey with EXACTLY the same issue and it's driving me nuts as it is less than a year old and barely used!
Mine is an SAC1153B model (150L 3hp single phase).
I bought it new in April and had not used it more than say 3 or 4 tank fulls since new when this began happening a few months ago and I've been trying to sort it since then.
Ordinarily I would have obviously sent it back but being on the Isle of Man this means I have to get a pallet and securely package it all back up myself for transit by ferry etc etc, and is generally a ballache, so I've been trying to sort it myself.
Mine will start when the tank is empty, or when part filled and warm, but not other than this. It's infuriating that I had a £100 24L Cosmo compressor from about 10 years ago that still runs fine despite all manner of abuse but spend £550 on an 'upgrade' and it won't even run!!
Anyway - this is what I've tried on mine to narrow it down:
1) Electrician has checked and confirmed that the power source is fine.
2) Oil level and type is fine (5/w50 synthetic in accordance with the instruction manual)
3) Motor starts very easily if the belt is removed
4) Compressor pump is VERY easy to turn by hand (ie 1 finger will turn it with ease) when belt is removed.
5) Unloader appears to be working correctly. It hisses from startup when tank is empty up to about 20psi, then stops hissing. When compressor stops it hisses as the pressure is dumped from cylinder/tank feed line.
6) Have replaced the check valve/non return valve, where the air feeds into the tank, as I was convinced this was the fault, but this did not really help
7) When the tank is empty, the compressor will normally start just fine
8) Once it succeeds in running, it will tend to restart easily, ie when warm. If it starts and I allow it to part fill the tank it will typically allow me to stop and start again repeatedly without problems.
9) Ambient temperature of my garage where it lives was around 10C when I began checking all this out. Not especially cold by any standards!
10) "Occasionally", the compressor trips the main fuse that feeds it from the house supply board (16 amp fuse, but not specifically a motor type fuse).
When this happens, it trips the fuse the instant the compressor start switch is deployed, and the motor does not turn at all. Resetting the fuse then means a second attempt at starting will not trip the fuse, but depending on the pump temp/tank fill state etc will either start or stall the thermal breaker. No idea why it just decides to trip the fuse but my sparky says all is fine on the power feed.
11) Air filter is clean!
12) Unloader valve is clean inside and doesn't "seem" to stick (hard to know though.....)
Sparky is adamant that the capacitors and motor are fine. He states that if either were faulty it would exhibit problems starting even with the belt off since a 3hp motor needs the capacitors to start correctly whether under load or not.
To me, and others I've asked, the most common cause of compressor problems is a faulty unloader, and the symptoms seem to suggest this is the case, BUT it does appear to be doing its job. It does a "PTCCHHHHHHHH!!!!!" when you stop the compressor from the unloader, so I can't see how if its venting there could still be pressure causing it to struggle on startup?
I'm at a loss if I'm honest. I don't want to have to randomly start buying replacement parts or to pay the local compressor place to investigate and repair. It cost me £550 so if should bloody well work given its nearly new, but sending it back will be a right cafuffle since it means getting a pallet, taking a day off work for the courier etc etc.
A replacement "pressure valve" (unloader/control unit) from Sealey is £40 delivered so I'd rather not have to buy one as part of this guessing game as I can't really afford to:
http://www.ccw-tools.com/Sealey-Power-Tools/Compressors/Belt-Drive-Compressors/Belt-Drive-Compressor-Spares/Sealey-SAC7250360000---Pressure-Switch/p-4-103-306-1681-34616/
I do have a spare new one that I bought for my Cosmo and never fitted as it turned out not to be the fault so I'm off to inspect that now and see if it might be compatible. If it is then I'll try swapping it out. If that works then I will send the Sealey one to them and respectfully ask that they send me a replacement FOC!
Hope this is ok posting on someone elses' thread but I thought given it's apparently the exact same issue and same brand it might be useful for us both to combine info and ideas.
Cheers
Jim
Cret
Member
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- 150
Cheers for the replies. 
Brightspark - my Sparky was originally going to swap the fuse out for a 'motor spec fuse' as he wondered if that might help, but since it was the thermal trip on the compressor that keeps going we figured it probably wouldn't make any difference otherwise it would be the actual 16amp fuse that kept tripping rather than the thermal breaker. Not saying it couldn't be that by any means as I'm game to try anything, but what would the rationale be behind it if that did solve the issue?
Yes it has two big caps in with the thermal breaker. I can do standard ish electrical/electronics stuff, but not entirely sure on the correct way of testing the health of a capacitor, and I'm wary about the things knowing how nasty they potentially can be! How long would these hold any charge for after the power has been turned off roughly? I only have a cheap & basic multimeter, so am not sure the best way to test these if that needs doing?
Oddly enough while out in the garage just now that very thought did occur to me that it might be possible it's just a bit 'tight' since it's barely been used at all, but then at the same time the pump is soooo easy to turn by hand that I can't see it would matter in reality. It might be worth a try if I am not getting anywhere with other tests though.
Anyway - an update (since finding someone with the same brand and same problem has renewed my enthusiasm, and since the bloody thing is in the way of where I'm trying to rebuild my bike!!!).
After scrutinising the spare control unit I had lying about, I removed the control unit/unloader device on the compressor. It's labelled as a Condor MDR2 for what it might be worth.
The new one is a cheap looking, unbranded thing with a pull up/push down switch instead of the rotary on/off switch on the Condor unit. Doubt it matters but anyway.
The actual unloader valve itself of the spare unit looks vastly inferior build quality (mostly plastic compared with brass).
Plumbed and wired it in anyway and tried the compressor. As often happens, the very first try the fuse itself tripped.
Second try the compressor started and ran (empty tank obviously) so at this stage no way to tell if it was an improvement.
I ran it up to 40psi in the tank then stopped it. Gave a healthy PSSHHHHHH! from the unloader.
Tried to restart and it wouldn't. Was tripping the thermal trip on the compressor each time I tried.
I noticed a slight hiss from one of the blank plugs on the unit so went and got a spanner and tightened it. Took me a few minutes as the right spanner was buried on the floor somewhere. After that I removed the unloader pressure feed line from the check valve on the tank and noted no residual pressure was there. This means the start problem didn't seem to be the unloader, and not the check valve either since if that was leaking (not fully closed) then air would have come out.
Put the pipe back and I tried again and it started, so maybe coincidence but it seemed a rest of a few minutes and it was happy to start again, warmish, and at 40psi.
Ran it up to 80 and stopped and the same thing happened. Wouldn't restart immediately, but after sitting for a couple of minutes it fired up ok.
So to recap I've tried two check valves/non return valves on the tank, two unloader/switch/control units and get the same problems more or less. No residual pressure in the lines, the correct spec/volume oil, a solid power supply (2.5mm twin & earth run of about 4-5m from fusebox then compressor hard wired to its own fused switch), pump turns easily by hand, and motor spins up with no belt. Will have to wait for it to cool after using it to check if it will restart with pressure in the tank now....
Tempted to try a lighter oil but can't imagine it should matter much when I have the exact right stuff and it's not really cold anyway. If it's that critical then it's a design flaw that everyone with that model would suffer surely?
It might well be the case that if it's run with outlet open it will work around the issue, but to me while that's a useful temporary solution it's by no means a satisfactory one, and if this has to be done when it's a new expensive machine and not even very cold then it's simply not fit for purpose IMO. Please don't take that the wrong way though as I appreciate the suggestion!
Cheers
Brightspark - my Sparky was originally going to swap the fuse out for a 'motor spec fuse' as he wondered if that might help, but since it was the thermal trip on the compressor that keeps going we figured it probably wouldn't make any difference otherwise it would be the actual 16amp fuse that kept tripping rather than the thermal breaker. Not saying it couldn't be that by any means as I'm game to try anything, but what would the rationale be behind it if that did solve the issue?
Yes it has two big caps in with the thermal breaker. I can do standard ish electrical/electronics stuff, but not entirely sure on the correct way of testing the health of a capacitor, and I'm wary about the things knowing how nasty they potentially can be! How long would these hold any charge for after the power has been turned off roughly? I only have a cheap & basic multimeter, so am not sure the best way to test these if that needs doing?
Oddly enough while out in the garage just now that very thought did occur to me that it might be possible it's just a bit 'tight' since it's barely been used at all, but then at the same time the pump is soooo easy to turn by hand that I can't see it would matter in reality. It might be worth a try if I am not getting anywhere with other tests though.
Anyway - an update (since finding someone with the same brand and same problem has renewed my enthusiasm, and since the bloody thing is in the way of where I'm trying to rebuild my bike!!!).
After scrutinising the spare control unit I had lying about, I removed the control unit/unloader device on the compressor. It's labelled as a Condor MDR2 for what it might be worth.
The new one is a cheap looking, unbranded thing with a pull up/push down switch instead of the rotary on/off switch on the Condor unit. Doubt it matters but anyway.
The actual unloader valve itself of the spare unit looks vastly inferior build quality (mostly plastic compared with brass).
Plumbed and wired it in anyway and tried the compressor. As often happens, the very first try the fuse itself tripped.
Second try the compressor started and ran (empty tank obviously) so at this stage no way to tell if it was an improvement.
I ran it up to 40psi in the tank then stopped it. Gave a healthy PSSHHHHHH! from the unloader.
Tried to restart and it wouldn't. Was tripping the thermal trip on the compressor each time I tried.
I noticed a slight hiss from one of the blank plugs on the unit so went and got a spanner and tightened it. Took me a few minutes as the right spanner was buried on the floor somewhere. After that I removed the unloader pressure feed line from the check valve on the tank and noted no residual pressure was there. This means the start problem didn't seem to be the unloader, and not the check valve either since if that was leaking (not fully closed) then air would have come out.
Put the pipe back and I tried again and it started, so maybe coincidence but it seemed a rest of a few minutes and it was happy to start again, warmish, and at 40psi.
Ran it up to 80 and stopped and the same thing happened. Wouldn't restart immediately, but after sitting for a couple of minutes it fired up ok.
So to recap I've tried two check valves/non return valves on the tank, two unloader/switch/control units and get the same problems more or less. No residual pressure in the lines, the correct spec/volume oil, a solid power supply (2.5mm twin & earth run of about 4-5m from fusebox then compressor hard wired to its own fused switch), pump turns easily by hand, and motor spins up with no belt. Will have to wait for it to cool after using it to check if it will restart with pressure in the tank now....
Tempted to try a lighter oil but can't imagine it should matter much when I have the exact right stuff and it's not really cold anyway. If it's that critical then it's a design flaw that everyone with that model would suffer surely?
It might well be the case that if it's run with outlet open it will work around the issue, but to me while that's a useful temporary solution it's by no means a satisfactory one, and if this has to be done when it's a new expensive machine and not even very cold then it's simply not fit for purpose IMO. Please don't take that the wrong way though as I appreciate the suggestion!
Cheers
Cret
Member
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- 150
By the way this unit looks identical to the one I just fitted. Doesn't really seem to behave any better with this than the Sealey (Condor) one so I'm assuming the unloader is not actually faulty:
http://www.ebay.co.uk/itm/90-120-PS...ompressors&hash=item4cfcec65ad#ht_2105wt_1163
http://www.ebay.co.uk/itm/90-120-PS...ompressors&hash=item4cfcec65ad#ht_2105wt_1163
So, to clarify, the fault is that the overload trip on the motor trips out, or the house MCB, on a pressure start when cold ?
Not surprised by the house MCB, it will need a type C to take the surge. Replace the the relevant breaker with a type C. Then, short out the overload trip on the motor, basically by just pulling the connections off and joining them together. Don't worry, for the purposes of this test it will be fine, the overload trip is there to prevent damage when the compressor is running unattended. Then see if it starts ok, that is without the motor struggling to start, it should start right up with almost no delay. If it does, the overload trip is either faulty or not the correct rating.
Not surprised by the house MCB, it will need a type C to take the surge. Replace the the relevant breaker with a type C. Then, short out the overload trip on the motor, basically by just pulling the connections off and joining them together. Don't worry, for the purposes of this test it will be fine, the overload trip is there to prevent damage when the compressor is running unattended. Then see if it starts ok, that is without the motor struggling to start, it should start right up with almost no delay. If it does, the overload trip is either faulty or not the correct rating.
