Alnico magnet

[leslie2000]

Hi everybody.

I have a customer who used an old alnico magnets in pickup for guita. he told us the magnetic property is about Br:12.85KGs, Hc:767Oe, BH(max): 5.9MGOe, while he required the gauss value of cylinder magnet D5x17mm, with 1150Gs.

My question is :

1. Is this possible? Because according to our calculating, this magnetic property will result in 1500Gs.

2. Can we use regular alnico 5 (LNG40) as replacement because LNG40 will generate this 1150Gs.

3. for Pickup, whether the gauss value is the most important factor? if we can garantee teh gauss vlue, it will not influnce the performance of pickup whether we will use high Hc grade magnet or regular magnets.

Thanks in advance for your kind suggestion.

 

[MagMike]

I haven't checked your numbers but the magnet is very likely stabilized down from the 1500 Gauss value. This is very common with Alnico.

Regarding your Q2: That's a decision between you and your customer

Regarding your Q3: You may find this link of interest:
thread340-105845

 

[leslie2000]

Thank you for your information, which is helpful. MagMike.

 

[EdStainless]

12.8 G and 750 Oe, sounds like good Alnico 5. It might even be 5-7. Has to be a cast grade, sintered can't reach these properties.

How old is it? It might be an Fe Cr Co 5 material. though I doubt it.

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Plymouth Tube

 

[leslie2000]

Edstainless: you are correct, the original design is using very old magnets back to 1970's. And now we want to find some other grade alnico magnets but have same gauss value (1150Gs). And according to our calculation, there are several options of alnico magnets, but now we are not sure even these gauss value is the same as the original magnets, the performance of pickup will be the same?

 

[EdStainless]

If your replacement material is a bit weaker then you may have to stabilize to lower field level. You need them all the same. This would lower overall output, but I can't see you going down too much.
A good Alnico 5 should be able to get this.

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Plymouth Tube