Amprobe AM240 multimeter - Page 1
Forum section: electronics / general

author: G7PSK
author_rank: Super Contributor
timestamp: January 10, 2012, 05:05:38 pm
content: I am thinking of buying a digital multimeter and was looking at the amprobe AM240 and wondered what thaughts anyone has on these. Also would like to know what voltage the frequency measurement can stand I want to be able to connect straight to 240 volt or even 415. Another meter I looked at would only take 20V on HZ range. No good for checking power sets Used to use tachometer but that usually means stripping safety guards from front end of power unit. I had a fluke many years ago but that blew up when measuring HZ despite supposedly being good for the voltage.

author: IanB
author_rank: Super Contributor
timestamp: January 10, 2012, 05:58:37 pm
content: Meters can usually measure frequency on the AC volts ranges, although sometimes the frequency range is a bit less than on the dedicated frequency setting.

author: G7PSK
author_rank: Super Contributor
timestamp: January 10, 2012, 06:05:14 pm
content: I only need 48 to 62 HZ the Fluke I had about 15 years ago would only read HZ on the dedicated range The specs as provided on line do not make it clear that HZ can be read on the volts range I don't need a lab grade meter as I am working on power circuits with never less than 4KVA of power available so no problems with the meter causing loading.

author: Unknown
author_rank: Unknown
timestamp: January 10, 2012, 06:51:08 pm
content: The overvoltage installation categories might be something to pay attention to. It sounds like the circuits you're working on are at least CAT III and maybe even CAT IV (check Fluke's document "ABCs of Multimeter Safety" for a description of CAT I-IV). CAT III 600 V may be a little low for your use, although CAT IV 600 V will probably be significantly more expensive.According to themanualyou need to set the meter to Hz to measure frequency or duty cycle. According to thedata sheetthe meter is protected up to 250 V DC or AC RMS, so 240 V sounds too close to the limit and 415 V is definitely out. This surprises me, I think IEC 61010 requires meters to handle the maximum rated voltage on all functions and ranges. Maybe it conforms to the old IEC 1010?

author: G7PSK
author_rank: Super Contributor
timestamp: January 10, 2012, 06:54:14 pm
content: It would appear that most meter manufacturers expect frequency mesurements to be done on audio outputs or something similar.

author: PetrosA
author_rank: Frequent Contributor
timestamp: January 10, 2012, 07:16:49 pm
content: If you need to work on equipment over 300V AC RMS, don't even mess with a meter that's not from a reputable company and rated for CAT IV. I wouldn't even look at anything for less than $100 new.

author: G7PSK
author_rank: Super Contributor
timestamp: January 10, 2012, 09:05:08 pm
content: amprobe is made by fluke and the one mentioned is about 60 something US dollars.

author: FenderBender
author_rank: Super Contributor
timestamp: January 10, 2012, 09:41:22 pm
content: Quote from: G7PSK on January 10, 2012, 09:05:08 pmWell it's not made BY Fluke directly. Fluke and Amprobe are owned by the same group, but I don't think they have too much real connection.