Re: D1D40 SSR's burning out?? Heatsinks [TANKS]

["flier" <FLIER-at-sbcglobal.net>]

BTW, on the heatsink/fans, the best solution is 
both.  A nice chunk of aluminum would work great, 
particularly with a fan blowing on it.  Even better, 
if you could scavenge a heatsink out of an old audio 
power amplifier, power supply, or even go out to 
Marlin P Jones surplus at www.mpja.com they have 
different kinds of surplus heatsinks.  Something with 
fins is the best.

Regards,

Ted


--- Original Message ---
From: "flier" <FLIER-at-sbcglobal.net>
To: <tanks-at-rctankcombat.com>, <tanks-at-rctankcombat.com>
Subject: Re: D1D40 SSR's burning out??  Don't use a 
diode!

>Whoa Grant!  My mistake.  Don't use a diode on your 
>motors!
>
>For some reason it totally slipped my mind we're 
>talking reversing motors.  You'd be fine in one 
>direction but the other would definately cause some 
>smoke...when the diode shorted.
>
>I think if you heatsink your SSRs properly you'll be 
>fine.  I need to let the Anvilus designer comment on 
>the necessity of including clamping diodes anywhere 
>as I don't think it's been a problem up to now.  The 
>Anvilus controller actually uses back EMF for 
braking 
>force when switching motor direction.  The software 
>is timed to take advantage.
>
>Sorry for the oversight!
>
>Ted
>
>
>--- Original Message ---
>From: Grant Mahalek <gmahalek-at-shaw.ca>
>To: tanks-at-rctankcombat.com
>Subject: Re: D1D40 SSR's burning out?? [TANKS]
>
>>Ted,
>>
>>Awesome advice....I really apppreciate the detailed 
>suggestions.  Now this 
>>is news I can use....
>>
>>I'am operating my system at 24vdc. So I suppose I 
>would be looking for a 
>>fast switching diode of 1A with a voltage rating of 
>about 24-40V. So a 24 - 
>>40V 1A fast switching diode connected right across 
>the motor should protect 
>>the SSR's from being burned out by back EMF?
>>
>>When you say install the diode "right across the 
>motor...", do you mean 
>>splice the diode directly into the positive and 
>negative wires leading into 
>>the motor(ie.- as close to the motor as possible).  
>Should the diode be 
>>installed in any particular direction? Can the 
diode 
>be installed at the 
>>terminal block on the motor controller where the 
>postive and negative leads 
>>connect from the motors?
>>
>>I'll go down to the local electronics store and 
pick 
>up some cooling fans as 
>>soon as I hear back from you.
>>
>>Regards,
>>
>>Grant
>>
>>
>>----- Original Message ----- 
>>From: "flier" <FLIER-at-sbcglobal.net>
>>To: <tanks-at-rctankcombat.com>; 
><tanks-at-rctankcombat.com>
>>Sent: Thursday, November 03, 2005 1:19 PM
>>Subject: Re: D1D40 SSR's burning out?? [TANKS]
>>
>>
>>> Hey Grant,
>>>
>>> If the motors stall, the current will go to the 
>max.
>>> I'm assuming the 15.4A spec is the typical current
>>> the motor will draw at a specified torque and at 
>some
>>> duty cycle.  You may very well be coming close or
>>> exceeding the 40A rating of the SSRs if the motor 
>is
>>> being 'held back'.  The D1D40 gets hot as heck
>>> dissipating the full 40A so they have to be 
mounted
>>> on a heatsink and may even need some cooling 
>airflow
>>> to switch the full spec 40A.  Check out the D1D40
>>> heatsink specs.  Even at 15 amps or so they're 
>gonna
>>> get up to 140 deg C!  Beyond 15A they must have a
>>> heatsink.
>>>
>>> In a nutshell, protection diodes keep the SSRs 
from
>>> seeing back EMF from an inductive load like a 
>motor.
>>> When the SSR breaks the circuit, the motor has 
some
>>> stored energy in it's coils that instantaneously
>>> feeds back to the open circuit.  The diode keeps 
>the
>>> SSR from seeing that spike.  Just pick a fast
>>> switching diode say 1A with a voltage rating 
that's
>>> at least equal or a little greater than your 
supply
>>> voltage.  If 12V, then a 20V 1A switching diode 
>will
>>> work.  It goes right across the motor.
>>>
>>> Take care,
>>>
>>> Ted
>>>
>>> --- Original Message ---
>>> From: Grant Mahalek <gmahalek-at-shaw.ca>
>>> To: tanks-at-rctankcombat.com
>>> Subject: Re: D1D40 SSR's burning out?? [TANKS]
>>>
>>>>Hey Ted,
>>>>
>>>>Thanks for the input Ted. I do not have 
>any "protect
>>> diodes" installed in
>>>>the circuit.  Are you referring to the "Transient
>>> Protection" using fast
>>>>recovery diodes with PIV rated greater than the
>>> supply voltage as
>>>>illustrated/described on the www.crydom.com
>>> website.  Can you suggest what
>>>>type and size of diode to use and how/where to
>>> install these diodes.
>>>>
>>>>I'am assuming when you say "dissipation/max draw
>>> issue" you mean the motor/s
>>>>are drawing in excess of 40 amps which may be
>>> burning out the D1D40 SSR's.
>>>>The motors are only rated at 24vdc, 15.4 amps. 
I've
>>> taken the drive system
>>>>apart....without the tracks or motor connected the
>>> gear reduction runs
>>>>freely. In the field tests where the SSR's burned
>>> out I was using boat
>>>>roller drive wheels....this did'nt work.....the
>>> drive wheels slipped even
>>>>when I had the tracks so tight the 1/2" drive-
>shafts
>>> were bending under the
>>>>load.
>>>>
>>>>Could you please explain what you mean
>>> by "dissipation.....issue"? Any
>>>>suggestions how this problem could be corrected?
>>>>
>>>>Oh, one last thing, I was talking with an
>>> Electronics Technician yesterday
>>>>in the LHS, he feels there may be a problem with 
>max
>>> current draw and
>>>>suggested installing resistors to limit the 
current
>>> flowing to the motors.
>>>>What do you think? Don't know what type or size or
>>> exactly where/how to
>>>>install.  Do you have any suggestions?
>>>>
>>>>Don't hesitate to provide technical answers as my
>>> buddy Mark Townsend, a
>>>>skilled electronics hobbyist is helping me out.
>>>>
>>>>I'am building new drive wheels today using plywood
>>> discs and rubber bungee
>>>>cord ie.-obviously a more successful design). I 
>will
>>> be measuring the no
>>>>load and full load(ie.-transmission and tracks
>>> installed) current on the
>>>>bench today or tomorrow.
>>>>
>>>>Thanks again, any ideas are appreciated!
>>>>
>>>>
>>>>Grant "thank goodnes for people more knowledgeable
>>> than me" Mahalek
>>>>
>>>>
>>>>----- Original Message ----- 
>>>>From: "flier" <FLIER-at-sbcglobal.net>
>>>>To: <tanks-at-rctankcombat.com>
>>>>Sent: Thursday, November 03, 2005 8:44 AM
>>>>Subject: Re: D1D40 SSR's burning out?? [TANKS]
>>>>
>>>>
>>>>> Hey Grant, it's Ted Callahan.
>>>>>
>>>>> If your max current is significantly below 40A,
>>> then the prob may be back
>>>>> EMF where the protect diodes come in although 
I'm
>>> skeptical.  I think you
>>>>> may have a dissipation/max draw issue.
>>>>>
>>>>> Regards,
>>>>> Ted
>>>>>
>>>>> --- Original Message ---
>>>>> From: Grant Mahalek <gmahalek-at-shaw.ca>
>>>>> To: tanks-at-rctankcombat.com
>>>>> Subject: Re: D1D40 SSR's burning out?? [TANKS]
>>>>>
>>>>>>Flier,
>>>>>>
>>>>>>Thanks for the suggestion.  I will be measuring
>>> the max current draw
>>>>>>today.
>>>>>>Oh by the way, what's your name....I'd like to
>>> address you by your name.
>>>>>>
>>>>>>Grant "I'am learning every day" Mahalek
>>>>>>
>>>>>>
>>>>>>----- Original Message ----- 
>>>>>>From: "flier" <FLIER-at-sbcglobal.net>
>>>>>>To: <tanks-at-rctankcombat.com>;
>>> <tanks-at-rctankcombat.com>
>>>>>>Sent: Wednesday, November 02, 2005 7:15 AM
>>>>>>Subject: Re: D1D40 SSR's burning out?? [TANKS]
>>>>>>
>>>>>>
>>>>>>> Grant,
>>>>>>>
>>>>>>> Have you measured your max current draw?
>>>>>>>
>>>>>>>
>>>>>>> --- Original Message ---
>>>>>>> From: Grant Mahalek <gmahalek-at-shaw.ca>
>>>>>>> To: tanks-at-rctankcombat.com
>>>>>>> Subject: Re: D1D40 SSR's burning out?? [TANKS]
>>>>>>>
>>>>>>>>Hi Norm,
>>>>>>>>
>>>>>>>>In Test #1 the right SSR got very hot.
>>>>>>>>
>>>>>>>>I forgot to check the SSR temperatures in 
>Test#2.
>>>>>>>>
>>>>>>>>Grant
>>>>>>>>  ----- Original Message -----=20
>>>>>>>>  From: Norman Wieser=20
>>>>>>>>  To: tanks-at-rctankcombat.com=20
>>>>>>>>  Sent: Tuesday, November 01, 2005 9:08 PM
>>>>>>>>  Subject: Re: D1D40 SSR's burning out?? 
>[TANKS]
>>>>>>>>
>>>>>>>>
>>>>>>>>  Hi Grant
>>>>>>>>
>>>>>>>>   Did the SSR's get very Hot ?
>>>>>>>>
>>>>>>>>  Norm
>>>>>>>>    ----- Original Message -----=20
>>>>>>>>    From: Grant Mahalek=20
>>>>>>>>    To: tanks-at-rctankcombat.com=20
>>>>>>>>    Sent: Tuesday, November 01, 2005 6:27 PM
>>>>>>>>    Subject: Fw: D1D40 SSR's burning out??
>>> [TANKS]
>>>>>>>>
>>>>>>>>
>>>>>>>>    Hi there,
>>>>>>>>
>>>>>>>>    I've run into a bit of a problem in the
>>>>>>> construction of my Hetzer.  =
>>>>>>>>I've burned out three Crydom SSR's with my
>>> Anvilus
>>>>>>> proportional motor =
>>>>>>>>controller.  I've sent off an email to
>>>>>>> www.crydom.com today in hopes of =
>>>>>>>>getting some suggestions.  The Crydom website
>>>>>>> mentions something called =
>>>>>>>>"Transient Protection" and protection of the
>>> SSR's
>>>>>>> using fast recovery =
>>>>>>>>type diodes with PIV rated greater than 
supply 
>=
>>>>>>>>voltage(....cool....unfortunately I don't
>>> completely
>>>>>>> understand this). =
>>>>>>>>Has anyone out there
>>>>>>>>
>>>>>>>>    In the "Tri-Pact News Service" article
>>>>>>> entitled "R/C Combat Vehicles =
>>>>>>>>Speed Controls" under the section "Other 
>Issues"
>>>>>>> various devices are =
>>>>>>>>recommended to limit power surges and radio
>>>>>>> interference.  After a small =
>>>>>>>>fix(installation of a CMOS NAND 4011 Gate) 
into
>>> the
>>>>>>> steering and =
>>>>>>>>throttle servo leads, radio interference is no
>>>>>>> longer a problem.
>>>>>>>>
>>>>>>>>    However, burning out these SSR's is 
>becoming
>>> a
>>>>>>> bit of a =
>>>>>>>>pain....xxo!!/?##.
>>>>>>>>
>>>>>>>>    Can anyone out there offer suggestions,
>>> detailed
>>>>>>> or otherwise on how =
>>>>>>>>to overcome this obstacle?  Any suggestions
>>> would be
>>>>>>> much appreciated.
>>>>>>>>
>>>>>>>>    Oh, by the way, the rubber boat roller 
>drive
>>>>>>> wheels did not work, =
>>>>>>>>the rubber was too hard and the drive wheels
>>> slipped
>>>>>>> in the tracks.  =
>>>>>>>>I'am going to use the "tried and true" TTS 
>rubber
>>>>>>> bungee cord wrapped =
>>>>>>>>plywood drive wheels.  And for those of you
>>>>>>> wondering about what =
>>>>>>>>thickness of drive-shaft to use, I support 
>Steve
>>>>>>> Tyng's suggestion to =
>>>>>>>>use a hardened steel shaft > 1/2 inch.  I've
>>> already
>>>>>>> bent both my 1/2 =
>>>>>>>>inch drive shafts in the minimal testing I've
>>> done
>>>>>>> so far.
>>>>>>>>
>>>>>>>>    Supper call....thanks for any help you 
guys
>>> can
>>>>>>> offer.
>>>>>>>>
>>>>>>>>
>>>>>>>>    Grant P. Mahalek
>>>>>>>>
>>>>>>>>    ----- Original Message -----=20
>>>>>>>>    From: Grant Mahalek=20
>>>>>>>>    To: support-at-crydom.com=20
>>>>>>>>    Sent: Tuesday, November 01, 2005 7:33 AM
>>>>>>>>    Subject: D1D40 SSR's burning out??
>>>>>>>>
>>>>>>>>
>>>>>>>>    Hello there,
>>>>>>>>
>>>>>>>>
>>>>>>>>    I'am a hobbyist using a pair of Crydom 
>D1D40
>>>>>>> SSR's with a motor =
>>>>>>>>controller to provide proportional speed 
>control
>>> for
>>>>>>> a custom built 1:6 =
>>>>>>>>scale radio control combat tank. The motor
>>> controller
>>>>>>> (Anvilus RC Relay =
>>>>>>>>SSR Motor Controller; Board h_050412, Manual
>>> 050425)
>>>>>>> is described in =
>>>>>>>>detail at www.anvilus.com . The motor and 
>control
>>>>>>> system is wired =
>>>>>>>>according to figure 3, page 5 of the manual.
>>> I'am
>>>>>>> using a pair of new =
>>>>>>>>electric scooter motors(MY1016) from
>>>>>>> www.unitemotor.com operated at =
>>>>>>>>24Vdc. Motor specifications: 24Vdc, 2750 rpm,
>>>>>>> 15.4amps, 280watts. There =
>>>>>>>>is a 40 amp automotive fuse installed in-line 
>on
>>> the
>>>>>>> each motor power =
>>>>>>>>lead.  No other circuit protection is 
provided.
>>>>>>>>
>>>>>>>>    I have burned out three(3) Crydom D1D40 
>SSR's
>>>>>>> thus far.  This is =
>>>>>>>>getting a little expensive for a hobby......
>>>>>>>>
>>>>>>>>    Can you help?
>>>>>>>>
>>>>>>>>    Circumstances of failures:
>>>>>>>>
>>>>>>>>    1.)Test #1; left SSR failed; left SSR -1
>>>>>>> terminal wires became loose =
>>>>>>>>during tank test run. Up to this time(20 
>minutes
>>> of
>>>>>>> run time), the =
>>>>>>>>electronics and drive system were operating 
>with
>>>>>>> full mixing and =
>>>>>>>>proportional speed control.  Right drive motor
>>> and
>>>>>>> right SSR became very =
>>>>>>>>hot.
>>>>>>>>
>>>>>>>>    2.)Test #2; right SSR failed after about 
20
>>>>>>> minutes of fully =
>>>>>>>>proportional run-time. No apparent loose
>>> electrical
>>>>>>> connections. No =
>>>>>>>>apparent mechanical binding in drive-train. 
>Right
>>>>>>> drive motor became =
>>>>>>>>very hot.
>>>>>>>>
>>>>>>>>    Apparently, there are twenty to thirty RC
>>> combat
>>>>>>> tanks using the =
>>>>>>>>same electronics(with Crydom SSR's) and drive
>>>>>>> systems with almost =
>>>>>>>>identical components with no problems.
>>>>>>>>
>>>>>>>>    Do you have any suggestions regarding the
>>>>>>> inclusion of circuits or =
>>>>>>>>components to protect the SSR's from being 
>burned
>>>>>>> out.  Could you please =
>>>>>>>>be very specific with any suggestions 
regarding
>>>>>>> protective circuits or =
>>>>>>>>components(ie.-component/circuit installation
>>> into
>>>>>>> motor control wiring =
>>>>>>>>and type and specific sizes of and sizes of 
any
>>>>>>> components).=20
>>>>>>>>
>>>>>>>>
>>>>>>>>    Thank you,
>>>>>>>>
>>>>>>>>
>>>>>>>>    Grant P. Mahalek
>>>>>>>>    gmahalek-at-shaw.ca
>>>>>>>>    403-948-6443(res)
>>>>>>>>    403-880-2070(bus, cell)
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>> 
>>
>>
>