Re: Bosch GRA53 36V Lawnmower - no motor
is there a pcb inside the motor with fets etc ?
is there a pcb inside the motor with fets etc ?
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Re: Bosch GRA53 36V Lawnmower - no motor
There is a PCB, yes, but the components on it are tiny. Let me get some pictures of it in case it is useful. I thought it was the Hall effect rotation sensor but I am probably incorrect.Comment
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Re: Bosch GRA53 36V Lawnmower - no motor
Here we go - this is what is on the board inside the motor. Three Hall Effect W32 transistors by the looks of it?
EDIT : If you were asking about the power circuit driving the motor, that is under the black resin in the lower module on the chassis. No way of knowing what the heck is under that lot!Attached FilesLast edited by DanielCoffey; 08-11-2023, 01:00 PM.Comment
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Re: Bosch GRA53 36V Lawnmower - no motor
UPDATE : I wrote to Bosch asking whether I needed just a replacement motor or a control board as well. They advised given the symptoms that the control board appeared to be working as expected and to try just a new motor first.
I was mistaken when I quoted the motor power in an earlier post. I had assumed it was 1800W because that is the power of the one in my smaller Honda but the Bosch was only fitted with a 1440W motor.
One day I may try making a Frankenmower by combining the Honda 1800W motor and control board in the Bosch chassis but until then I have ordered and received a new 1440W Bosch 36V motor assembly.
It turns out that Bosch were correct - the control board does behave as expected and spins the new motor. It only does so briefly because I assume that without a blade it goes overspeed and shuts off. Once I have cleaned the chassis I will fit the motor and test it with the blade attached.
I do have one question though... the shaft seal. Bosch still only use an impact seal to prevent the lower motor bearing from being damaged by stones. It does not keep dirt or water out of the motor and even has a fairly wide gap between the seal and the shaft.
Given that the motor does not contain any oil or grease, is there a better type of seal that would keep the water and dust out of the motor? The dimensions without the Bosch impact seal are 37mm OD, 25mm ID and up to 6mm height. I also hav no idea of the correct way/tool for removing the existing impact seal which is pressed into place to cover the lower bearing and circlip.Attached FilesComment
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Re: Bosch GRA53 36V Lawnmower - no motor
I would not recommend that you try to remove the seal unless you plan on taking the motor apart here what I would do and recommend if have place where they make caskets for machines and equipment see if can get a rubber seal made at least 1/4” inch thick that will fit tight on the motor shaft and will cover the whole seal and over hang it at least a few mm this will help keep most of dirt and rocks from damaging the seal now you might have to use a hose clamp or glue the rubber to hold it up on the shaftComment
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Re: Bosch GRA53 36V Lawnmower - no motor
That's a good idea... the shaft is 25mm and there is a good 10mm of clearance (5mm each side). If I could find some 25mm ID thick walled hose I could cut enough that the blade would keep it in place but not long enough to jam it tight up against the seal. That would help keep the water out a bit better.
EDIT : it would interfere with the indent on the shaft for a 22mm spanner to assist with blade removal but it is a starting point to think about.Last edited by DanielCoffey; 09-05-2023, 04:27 AM.Comment
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Re: Bosch GRA53 36V Lawnmower - no motor
maybe a big o-ring over the shaft and greased would helpComment
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Re: Bosch GRA53 36V Lawnmower - no motor
Nice idea, thanks. Easy and cheap too.Comment
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Hi friends of electronics
What you see in the video and pictures attached is the circuit for charging the batteries of a DC motor.
The problem is that this circuit cannot charge the batteries (3 1800mAH NiMH batteries) any more. When the circuit was OK, its green LEDs lit up one at a time to show that the batteries have charged more. But now that the circuit is flawed, LEDs light up as you see in the video and at the same time successive beeps are heard.
Please help me fix this circuit.
(the datasheet of the IC: https://pdf.datasheet.live/28... -
Hello, all.
Cyberpower Battery Backup Unit.
I bought two new ML18-12 batteries through Amazon (They have already refunded my money for the two batteries as we thought the batteries might have been bad.)
When I got them in, they were not fully charged. I connected them to the UPS and waited 24 hours before connecting any networking equipment.
In parallel, they read 24v, but within 24 hours, the meter on the front of the unit dropped from 4 to 3 bars on the battery charge indicator.
Checking the voltage, it was down to 22v.
I quickly removed everything... -
Hi,
i am asking for some Help.
I have one of these Nescafe Aeroccino (Milk Frother) things with a bad motor.
The Motor didn´t start anymore and internet is full of users just swapping the motor for a Mabuchi RF-500TB-12560.
So i got a few of these from Banggood.
I swapped the motor and now i have a new fault condition.
In a working Frother you would press the start button, it will light red and work for a few minutes.
If you press longer it will light blue and just mixup the milk.
With the new Motor it just starts... -
hi there,im having a look at repairing a wood lathe for my dad,(charnwood w821)the problem is when turning up the variable speed control,the motor starts to stop and start by itself,if i continue to turn up the speed it will trip the mcb in the consumer unit,there is also a slight smell of burning from the speed controll box.,Another strange symptom is the lathe can be unplugged from the mains after switching it off and the motor will spin a couple of times by itself,so far ive put a new speed controll potentiometer on and new motor brushes,ive also tested the motor windings and everything looks... -
Order my parts from mobilesentrix.com and iPhone batteries have been excellent. Recently got 3x bad A1534 (2015) batteries. All would work until ~30-40+% and drop to < 10% instantly. Typical sign of cheap batteries.
Perhaps the less popular A1534 model's aftermarket batteries are more source limited. Just find it surprising quality from mobilesentrix (usually fairly high quality aftermarket parts) have been so poor.
BTW, this isn't the only defective parts I've had from mobilesentrix. Amongst others including iPad Air touch screen and A1989 touch bar (display was...
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