WYDT
Contributor
ZZZZIIIIINNNNG! It was my idea...
Silent-Submersion vs. Gavin
- Thread starter lucid
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
- Status
ZZZZIIIIINNNNG! It was my idea...
WYDT,
You can have the last word about scooter preference after I say this one last thing.
First off you should read more about DC or AC motors if you think because their continous duty that they dont produce heat. When they heat up they need some way to dispate the heat and this is is why SS scooters use aluminum housings on their motors. Even if they only get warm and you have no way to get rid of it it still ends up being wasted energy.
I can see why your trying to justify your scooter and its because you paid allot of money for it and you dont want someone bashing it. Well I paid allot for mine too and I'm in this post for the same reasons and thats also why I purchased an SS their better built.
The speed thing . Gavins are no faster. Even if they were who cares how many times are you going to half to start and stop that scooter to adjust for prop pitch because your going to fast to go through small tunnels. Remember start and stop brings on higher amp draws which produces more heat. You say you've rode both, so have I. I've also had both apart side by side (big deal).
Motors produce heat "FACT" and if there's no way to get rid of it, eventually starts to burn the windings then eventually starts to burn out the motor. Ask any electrical engineer, ask any technician that works on motors every day (me). Ask Gamble who has worked on scooters for along time and still does. I'm in no way saying Gavins are junk but I am saying SS scooters are way better built.
Go ahead fire away. If there's any engineers reading this please tell me what I'm wrong about and if I'm right about any of it. Physics tells me I'm right.
Every device that converts one form of energy to another, loses some in the process. All of the energy consumed, eventually ends up as heat. The more efficient the process, the less heat is generated internally.
The little screw you talk of. You know the one you say locks off the throttle by friction instead of other means. This threads into a hole and does not use friction to secure it. It stays locked.
I'm not bashing you so please dont respond in a non-proffesional way. I'm just trying to explain to you that your mis-informed.
You can have the last word about scooter preference after I say this one last thing.
First off you should read more about DC or AC motors if you think because their continous duty that they dont produce heat. When they heat up they need some way to dispate the heat and this is is why SS scooters use aluminum housings on their motors. Even if they only get warm and you have no way to get rid of it it still ends up being wasted energy.
I can see why your trying to justify your scooter and its because you paid allot of money for it and you dont want someone bashing it. Well I paid allot for mine too and I'm in this post for the same reasons and thats also why I purchased an SS their better built.
The speed thing . Gavins are no faster. Even if they were who cares how many times are you going to half to start and stop that scooter to adjust for prop pitch because your going to fast to go through small tunnels. Remember start and stop brings on higher amp draws which produces more heat. You say you've rode both, so have I. I've also had both apart side by side (big deal).
Motors produce heat "FACT" and if there's no way to get rid of it, eventually starts to burn the windings then eventually starts to burn out the motor. Ask any electrical engineer, ask any technician that works on motors every day (me). Ask Gamble who has worked on scooters for along time and still does. I'm in no way saying Gavins are junk but I am saying SS scooters are way better built.
Go ahead fire away. If there's any engineers reading this please tell me what I'm wrong about and if I'm right about any of it. Physics tells me I'm right.
Every device that converts one form of energy to another, loses some in the process. All of the energy consumed, eventually ends up as heat. The more efficient the process, the less heat is generated internally.
The little screw you talk of. You know the one you say locks off the throttle by friction instead of other means. This threads into a hole and does not use friction to secure it. It stays locked.
I'm not bashing you so please dont respond in a non-proffesional way. I'm just trying to explain to you that your mis-informed.
Aquamaniac
Contributor
- Messages
- 1,257
- Reaction score
- 5
As an electrical Design engineer, specializing in electric motor/generator insulation systems, All I want to say is.......
You really should be more knowledgable in topic you are discusing before you go rubbing people up the wrong way.
In some respects you are correct, but in some you are far wrong, read up a bit more. Look into I squared R losses. The answers are all there.
Aquamaniac
Contributor
- Messages
- 1,257
- Reaction score
- 5
Lemme also just point out that WYDT said Gav's do not get hot.
THAT is a FACT.
BIG differance between a warm motor and a HOT motor.
If your a motor winder, you would also know about F Class and H class insulation systems, they can get pretty warm before doing ANY damage to the windings.
THAT is a FACT.
BIG differance between a warm motor and a HOT motor.
If your a motor winder, you would also know about F Class and H class insulation systems, they can get pretty warm before doing ANY damage to the windings.
So tell me what I'm right on and what I'm wrong on. Blue windings found on Gavin motors isnt from heat? Never said I was a motor winder. Said I was a Technician. Never said what kind but I do work with allot of different motors and I know they heat up. I never said anything about them getting hot but yes they do. Its caused by the constant start and stop which pulls high amps and thats with any non-variable speed scooter. So tell me what part of my post was wrong. This is not me trying to be a wise ass. Just me trying to learn as much as I can. Thats why I read this board every day. There is some very knowledgable people on here.
Since you are an Engineer, and actually I believe you. Which is better to house a motor in plastic or aluminum?
Wasnt trying to rub anyone the wrong way thats just how it comes out when you write on these boards. I just think I'm right. Maybe not about every little detail but about it being a better product, that I'm sure of. WYDT I dont even know him but knowing he owns a scooter and dives I'm sure I'd like him.
Look at the quality between the 2.
http://www.gavinscooters.com/images/tail_end_gold_superconnectors.jpg
http://www.silent-submersion.com/images/UV18batt.jpg
Since you are an Engineer, and actually I believe you. Which is better to house a motor in plastic or aluminum?
Wasnt trying to rub anyone the wrong way thats just how it comes out when you write on these boards. I just think I'm right. Maybe not about every little detail but about it being a better product, that I'm sure of. WYDT I dont even know him but knowing he owns a scooter and dives I'm sure I'd like him.
Look at the quality between the 2.
http://www.gavinscooters.com/images/tail_end_gold_superconnectors.jpg
http://www.silent-submersion.com/images/UV18batt.jpg
Aquamaniac
Contributor
- Messages
- 1,257
- Reaction score
- 5
Im not qualified to compare Gav's to SS's. I have never owned either. (but Im saving madly)
As far as the Gav's getting hot, I can only go buy what friends tell me.
What makes a better housing, plastic or Aluminum?
Open ended question.
If the motor design is poor, and inefficient, or in other words generates too many I2R losses (gets warm), then an aluminum housing would be a better option, so as to dissapate the heat generated. Remember you only need to keep the motor below its insulation class rating, most small DC motors are F class, therefore need to be kept below 155 degrees Celcius.
BUT if the motor design is good, and the operator does not overload it, then plastic is OK. This is because an efficient, correctly loaded motor does NOT generate excessive heat.
How do you make an efficient motor, or one that runs cool?
Well, that is a question that we ask our engineering staff at every board meeting , its what we strive toward.
Here are a few things.
1. Ensuring interlamination insulation is good quality, and making sure that there are not "shorts" in the lamination stack. Most of these problems occur when rewinding and repairing motors.
2. Ensure that the core is efficient, and "matched" to the windings. This is the core principals in winding design. Too much or too little back iron, and the losses will be high.
3. Most importantly, GET MORE COPPER IN THE SLOT!!!!!. More copper and less insulation in the slot, makes a more efficient motor. This is the MAJOR focus of new designs in windings. It is the biggest issue we have with GE and Siemens Westinghouse.
By reducing the thickness of insulation on the wire, without reducing dielectric strength, you can increase the efficiency dramatically, This is provided the winding data is modified accordingly.
Now, if you do want redesign a motor or generator, and DO need high quality insulation materials, that WILL increase efficiency, call the Engineering Manager at www.electricalfibers.com , I hear he is a Great bloke, and more than willing to help you out!
dave
As far as the Gav's getting hot, I can only go buy what friends tell me.
What makes a better housing, plastic or Aluminum?
Open ended question.
If the motor design is poor, and inefficient, or in other words generates too many I2R losses (gets warm), then an aluminum housing would be a better option, so as to dissapate the heat generated. Remember you only need to keep the motor below its insulation class rating, most small DC motors are F class, therefore need to be kept below 155 degrees Celcius.
BUT if the motor design is good, and the operator does not overload it, then plastic is OK. This is because an efficient, correctly loaded motor does NOT generate excessive heat.
How do you make an efficient motor, or one that runs cool?
Well, that is a question that we ask our engineering staff at every board meeting
, its what we strive toward.Here are a few things.
1. Ensuring interlamination insulation is good quality, and making sure that there are not "shorts" in the lamination stack. Most of these problems occur when rewinding and repairing motors.
2. Ensure that the core is efficient, and "matched" to the windings. This is the core principals in winding design. Too much or too little back iron, and the losses will be high.
3. Most importantly, GET MORE COPPER IN THE SLOT!!!!!. More copper and less insulation in the slot, makes a more efficient motor. This is the MAJOR focus of new designs in windings. It is the biggest issue we have with GE and Siemens Westinghouse.
By reducing the thickness of insulation on the wire, without reducing dielectric strength, you can increase the efficiency dramatically, This is provided the winding data is modified accordingly.
Now, if you do want redesign a motor or generator, and DO need high quality insulation materials, that WILL increase efficiency, call the Engineering Manager at www.electricalfibers.com , I hear he is a Great bloke, and more than willing to help you out!
dave
RichLockyer
Guest
From those photos it is impossible to tell if there is a REAL quality difference.
SS has an aluminum motor housing, Gavin has plastic. No effective difference though... the heat from the motor is still contained within the outer housing so neither will result in significantly reduced motor temperatures... there is still no good heat conduit leading to the water, unless the SS tailcone is black anodized aluminum. The SS housing looks cooler, but rule #6 doesn't apply on the bench
The SS legs look solid (I assume they are stainless)... not sure if I like the grips.
Battery connectors?
Yes, the SS connectors are high-quality Sermos power connectors with a solid, positive locking action.
The Gavin uses a connector that I am not familiar with, however, it DOES use gold contacts, which are superior in corrosion resistance. I am not aware of Sermos connectors (of that size) being available with gold contacts.
I'd actually give points to the Gavin for this part of the design for a couple of reasons:
1 - You aren't flexing the wire leads when opening the connector
2 - The positive lock isn't needed as there's no tension on the connector in the Gavin design. One side is fixed to the bulkhead.
3 - It is impossible to tell, but the SS APPEARS to simply have a hole in the bulkhead where the wire passes through from the battery compartment to the motor compartment. The Gavin is sealed, and uses the bulkhead jacks that you can see in the photo.
IF this passage is not sealed, then hydrogen from the battery compartment will pass into the motor compartment. This happened in a friend's radio controlled submarine... he made the local papers.
SS has an aluminum motor housing, Gavin has plastic. No effective difference though... the heat from the motor is still contained within the outer housing so neither will result in significantly reduced motor temperatures... there is still no good heat conduit leading to the water, unless the SS tailcone is black anodized aluminum. The SS housing looks cooler, but rule #6 doesn't apply on the bench
The SS legs look solid (I assume they are stainless)... not sure if I like the grips.
Battery connectors?
Yes, the SS connectors are high-quality Sermos power connectors with a solid, positive locking action.
The Gavin uses a connector that I am not familiar with, however, it DOES use gold contacts, which are superior in corrosion resistance. I am not aware of Sermos connectors (of that size) being available with gold contacts.
I'd actually give points to the Gavin for this part of the design for a couple of reasons:
1 - You aren't flexing the wire leads when opening the connector
2 - The positive lock isn't needed as there's no tension on the connector in the Gavin design. One side is fixed to the bulkhead.
3 - It is impossible to tell, but the SS APPEARS to simply have a hole in the bulkhead where the wire passes through from the battery compartment to the motor compartment. The Gavin is sealed, and uses the bulkhead jacks that you can see in the photo.
IF this passage is not sealed, then hydrogen from the battery compartment will pass into the motor compartment. This happened in a friend's radio controlled submarine... he made the local papers.
WYDT
Contributor
First off you should read more about DC or AC motors if you think because their continous duty that they dont produce heat. When they heat up they need some way to dispate the heat and this is is why SS scooters use aluminum housings on their motors. Even if they only get warm and you have no way to get rid of it it still ends up being wasted energy.
I'll defer to Dave on this part of the argument as I am not an engineer and he seems to have summed it up quite well.
I can see why your trying to justify your scooter and its because you paid allot of money for it and you dont want someone bashing it. Well I paid allot for mine too and I'm in this post for the same reasons and thats also why I purchased an SS their better built.
This is the part I disagree with you on. They are not better built and I believe the argument has been made effectively for the Gavin already. I'm not saying the SS is a POS, I'm just saying the Gavin is better. We're talking about "better" being a very relative term. Think of it like 14kt gold vs 18kt gold.
The speed thing . Gavins are no faster. Even if they were who cares how many times are you going to half to start and stop that scooter to adjust for prop pitch because your going to fast to go through small tunnels. Remember start and stop brings on higher amp draws which produces more heat. You say you've rode both, so have I. I've also had both apart side by side (big deal).
The speed thing isn't a big deal as they both use the same rewound motors. I was just commenting mine seems a bit faster than the SS I dove but maybe it's not as it was a few months between driving the SS and my Gavin. No big deal here, they have "similar" speed.
Motors produce heat "FACT" and if there's no way to get rid of it, eventually starts to burn the windings then eventually starts to burn out the motor. Ask any electrical engineer, ask any technician that works on motors every day (me). Ask Gamble who has worked on scooters for along time and still does. I'm in no way saying Gavins are junk but I am saying SS scooters are way better built.
"way better built"? This is where I have a big problem. They are not. An aluminum motor housing does not make the scooter "way better built" and I believe Dave has proven that. Rich makes some good points as well.
Go ahead fire away. If there's any engineers reading this please tell me what I'm wrong about and if I'm right about any of it. Physics tells me I'm right.
Once again I'll defer to Dave...
Every device that converts one form of energy to another, loses some in the process. All of the energy consumed, eventually ends up as heat. The more efficient the process, the less heat is generated internally.
Once again I'll defer to Dave...
The little screw you talk of. You know the one you say locks off the throttle by friction instead of other means. This threads into a hole and does not use friction to secure it. It stays locked.
I'm pretty sure the "lock" on the SS I dove did NOT thread into a hole. Maybe Rodney has changed that as he should. Even if he has it can still get locked ON and that's not a good thing. Cruise control?? More like death control!
I'm not bashing you so please dont respond in a non-proffesional way. I'm just trying to explain to you that your mis-informed. [/B]
Looks like you are the one who's mis-informed but I'm not trying to bash you or SS either. I've said several times in this thread that SS is a good machine, I just believe and am backed up well here that Gavin is better. Not night and day better but better.
DSAO!!
Rob
RichLockyer
Guest
Even if the SS is better, is it good enough to be worth $100, $200, and $400 more than the Gavin?
I really hate to bring price into it, since cost is for strokes and a good quality product is worth it at ANY price (especially if it's saving your butt), but when you have two quality products that are of apparent equal quality, you then need to start taking that into consideration.
It makes sense that the Magnum scooters would cost more than the short bodies, but this takes us back to George's and the basic DIR philosophy of use the right tool for the job at hand. The cost issue has been eliminated as a factor is deciding what scooter would be purchased... if you need a small scooter for simple OW dives, you get the short. If you need hours of run time, you get the magnum.
While I'm sure that George doesn't lose any money on any of them, he makes a little more on the shorts while he makes a little less on the magnums. I'd be interested in seeing the sales figures but I'd be willing to bet that George sells a higher percentage of magnums while SS sells a higher percentage of shorts.
- Status
Similar threads
