In response to Almond's answer: I am a professional installer, and my digital multimeter is the most-used tool in my box. If you are going to be working with car audio, as a profession or a hobby, then you need to own a multimeter. A test light does not cut it. You do not have to spend a lot; you can get a $20-$40 meter at Sears or Radio Shack that will work perfectly well. A test light wo not show you the difference between 9 volts and 12 volts at the radio power supply, but that can be the difference between a working radio and a dead one.
1. Why do you have to use the nominal voltage of the transformer for the no-load or open-circuit test?
I think I understand your question so first here's a representation of the equivalent circuit of a transformer: -Under no load conditions the only current flowing into the primary is the current taken by the "parallel components" Xm and Rc. For a normal power transformer that current will be small compared to the current normally taken by the primary when the secondary is driving a load. For that reason you can ignore (short circuit) Xp and Rp and of course the secondary is only producing an open circuit voltage so Rs and Xs are of no consequence.The "thing" in the middle that looks like a transformer is a perfect power transformer and because no current is being delivered to the secondary that perfect transformer takes no current.So, it boils down to Rc and Xm being connected to the incoming power and no further components need to be analysed.I was wondering why exactly you have to use the nominal voltage of the transformer for the open-circuit or no-load test.There is one very important reason for this and that is core saturation - if you do not use the normal applied voltage you will either have too much saturation or too little and you wo not have a representive measurement. Saturation of the core is non-linear with voltage so it's important to use the right applied voltage. Look at the BH curve to see why: -You can see that it is very non-linear once you start approaching saturation and, most transformers will be designed to run at a magnetic field strength (H) in the early to mid areas of saturation. This of course means a smaller transformer size and less iron. Commercial reasons prevail.So, to do the test justice you need to run at nominal levels.If you were doing a test to find out the values of the series components then you would run the primary from a variac and short circuit the output. The sort of voltage that is now applied is a fraction of the nominal voltage so core losses are low (very linear BH curve) and eddy current losses (Rc) are also quite small.
2. Measuring floating gate potential with minimal leakage current
If this is for professional use, use an Electrometer such as this. This type of meter has an input impedance of 10^14 which is adequate to measure voltage in the leakage environment you have. There are a huge range of devices spanning low cost to high cost. You could build an electrometer if you were willing, and here might give you a starting point using an LMC662.If you are simply DIY experimenting then you can build/buy an electroscope. These are not easily calibrated, but can provide good comparative measurements of charge on a point. You could get something like this for $50 or less
3. Extension Cord for 20 amp load and other heavy loads?
Every 30' is about 2% voltage drop. Voltage is indirectly proportional to Amperes thus as Voltage goes down Amperes goes up. Extension cords are for temporary applications agreed but over time your motors will wear out faster. If I were in the carpet cleaning business I would only use 10AWG for all my needs regardless.
4. Bad voltage regulator?
There would be no way to tell for sure if something was frying them, but would suggest to you this would be highly unlikely. It is completely within reason for the rebuilt alternator to have gone bad ... that's why they have a warranty. Yes, it's a PITB to take on and off, but at least it did not cost you anymore than an extra trip to the store.
Copyright © 2021 NOYAFA | Sitemap
{"site":{"site_id":3160,"site_type":1,"site_domain":"noyafatester.com","domain_mode":2,"original_domain":"noyafatester.com","language_code":"en","is_init_domain":0,"is_shop":false,"is_ssl":1,"lang_prefix":"/","animate_name":"none"},"page":{"page_id":30464,"page_type":"ai_article_detail","page_code":423,"page_url":"/ai-article/voltage-meter-and-voltage-tester.html","page_source":"","allowAnimat":0,"content_id":659,"content_type":5,"detail_thumb":"https://img.yfisher.com/1617351473140.jpg","detail_title":"Voltage Meter and Voltage Tester?","moq":1},"translateList":{"A new item has been added to your Shopping Cart":"A new item has been added to your Shopping Cart","account":"account","Account Name":"Account Name","Account Number":"Account Number","Account is not exists":"Account is not exists","account security":"account security","Active Commission":"Active Commission","Add a review on the product":"Add a review on the product","Add to":"Add to","Add to Cart":"Add to cart","address book":"address book","affiliate links":"affiliate links","all":"all","All Orders":"All Orders","Already commented":"Already commented","Are you sure to cancel this withdrawal?":"Are you sure to cancel this withdrawal?","Are you sure to delete the selected items?":"Are you sure to delete the selected items?","Are you sure you want to delete it?":"Are you sure you want to delete it?","Awaiting Payment":"Awaiting Payment","Awaiting Shipment":"Awaiting Shipment","Back":"Back","Bank Transfer":"Bank Transfer","bank address":"bank address","basic information":"basic information","Buy":"Buy","Buy Now":"Buy Now","bank name":"bank name","city":"city","Copy successful":"Copy successful","Copy failed":"Copy failed","Can Extract":"Can Extract","Currency Type":"Currency Type","Cancel":"cancel","Cancel the success":"Cancel the success","Cancelled":"Cancelled","Choose a country":"Choose a country","Choose Coupon":"Choose Coupon","Choose items":"Choose items","Clear":"Clear","Clear Search":"Clear Search","Comment Successful!":"Comment Successful!","Comment Failed!":"Comment Failed!","Commission Details":"Commission Details","Commission":"Commission","Commission Status":"Commission Status","commodity payment":"commodity payment","completed":"completed","Completed":"Completed","Condition not met":"Condition not met","Confirm":"Confirm","Confirm password is inconsistent with new password":"confirm password is inconsistent with new password","Congratulations":"Congratulations","Congratulations! You are got a coupon.":"Congratulations! You are got a coupon.","Congratulations! You are got all coupons.":"Congratulations! You are got all coupons.","Continue":"Continue","Continue Shopping":"Continue Shopping","Copy the code and use it directly in the shopping cart.":"Copy the code and use it directly in the shopping cart.","Country":"Country","Coupon code":"Coupon code","Coupon List":"Coupon list","Date":"Date","days after receiving":"days after receiving","Design customization":"Design customization","Do not use any discount":"Do not use any discount","Earliest":"Earliest","Export successful":"Export successful","Export failed":"Export failed","email":"email","email format does not match":"email format does not match","Estimated Delivery Time":"Estimated Delivery Time","Effective Order Count":"Effective Order Count","Effective Sale Amount":"Effective Sale Amount","Expense":"Expense","expired":"expired","export a report?":"export a report?","Failed to upload files.":"Failed to upload files.","FAQ":"FAQ","Find Parts":"Find Parts","for order over":"for order over","Free":"Free","Free Quote & Information Request":"Free Quote & Information Request","Free Shipping":"Free Shipping","Get":"Get","Get coupons":"Get coupons","Get discount":"Get discount","Get it":"Get it","Get it after logging in and use it in the shopping cart.":"Get it after logging in and use it in the shopping cart.","Go to Page":"Go to Page","Highest Price":"Highest Price","home":"home","Hot Sale":"Hot Sale","Income":"Income","Incorrect form format":"Incorrect form format","Inquiry":"Inquiry","join guide":"join guide","Last 30 days":"Last 30 days","Last 7 days":"Last 7 days","Links report":"Links report","Loading":"Loading","Lowest Price":"Lowest Price","Match Product":"Match Product","Merchant Free Shipping":"Merchant Free Shipping","message":"message","Most Popular":"Most Popular","my account":"my account","my coupons":"my coupons","my inquiry":"my inquiry","my orders":"my orders","my reviews":"my reviews","my wishlist":"my wishlist","name":"name","New Arrival":"New Arrival","Newest":"Newest","No Quotation":"No Quotation","No time limit":"No time limit","Not deleted":"Not deleted","not valid yet":"not valid yet","Off":"Off","Offers and Discounts":"Offers and Discounts","ok":"ok","Only DOC,DOCX,PDF,PNG,JPEG and JPG files can be uploaded":"Only DOC,DOCX,PDF,PNG,JPEG and JPG files can be uploaded","optional":"optional","order notes":"order notes","Order over":"Order over","order id":"order id","order status":"order status","order amount":"order amount","Orders Report":"Orders Report","Other":"Other","Password contains at least numbers and letters length should be 6-20":"password contains at least numbers and letters length should be 6-20","Password is invalid":"Password is invalid","Password length should be 6-20":"Password length should be 6-20","Paypal":"Paypal","paypal payment":"paypal payment","Pending":"Pending","Pending Commission":"Pending Commission","personal info":"personal info","Please click ’click to continue’ to retry.":"Please click \"click to continue\" to retry.","Please contact customer service for cash withdrawal":"Please contact customer service for cash withdrawal","Please enter a valid email address":"Please enter a valid email address","Please enter the verification code":"Please enter the verification code","Please login in first":"Please login in first","Please select attribute":"Please select attribute","Please select country/region":"Please select country/region","Please select superior":"Please select superior","Please select the number of ratings.":"Please select the number of ratings.","Please select your country":"Please select your country","Please upload the invoice file":"Please upload the invoice file","Processing":"Processing","Product Name":"Product Name","Please fill in the delivery address before selecting the payment method":"Please fill in the delivery address before selecting the payment method","promotion center":"promotion center","Promotion Link Click Amount":"Promotion Link Click Amount","Promoted link clicks":"Promoted link clicks","Promotion Order Count":"Promotion Order Count","Promotion Reports":"Promotion Reports","read more":"read more","Received commission":"Received commission","Refund":"Refund","Refuse":"Refuse","Region":"Region","Register Success":"Register Success","Remittance":"Remittance","Reviews":"Reviews","reports":"reports","Sale ends in":"Sale ends in","Save in wishlist":"Save in wishlist","Search":"Search","swift code":"swift code","Select how to share":"Select how to share","Select premium items to increase your chances of making money":"Select premium items to increase your chances of making money","Share items to your channels.when other purchase a from your link, you can get commission.":"Share items to your channels.when other purchase a from your link, you can get commission.","Share Product":"Share Product","shipment successful":"shipment successful","Shipping":"Shipping","Shipping Address":"shipping address","Size guide":"Size guide","Small Text":"Small Text","Small Title":"Small Title","Sort By":"Sort By","Sales Amount":"Sales Amount","State/Province/Territory":"State/Province/Territory","Successfully delete":"Successfully delete","Successfully save":"Successfully save","Thank you for trying":"Thank you for trying","The account has been deactivated, please contact customer service to activate":"The account has been deactivated, please contact customer service to activate","the content can not be blank":"the content can not be blank","The coupon code has been copied and used in the shopping cart.":"The coupon code has been copied and used in the shopping cart.","The file name cannot exceed 100 characters":"The file name cannot exceed 100 characters","The file size cannot exceed 2MB":"The file size cannot exceed 2MB","The number of withdrawals on the day has been capped":"The number of withdrawals on the day has been capped","The subscription is successful, thank you for your participation":"The subscription is successful, thank you for your participation","The user center is out of service. Please contact customer service":"The user center is out of service. Please contact customer service","There is no amount to withdraw":"There is no amount to withdraw","There is no data to export":"There is no data to export","This is Text":"This is Text","This is title":"This is title","This transaction has failed.":"This transaction has failed.","Time to shop":"Time to shop","Tips":"Tips","To be commented":"To be commented","Total":"Total","Tutorial":"Tutorial","This Supplier/Shipping Company does not deliver to your selected Country/Region.":"This Supplier/Shipping Company does not deliver to your selected Country/Region.","Update password success":"Update password success","Upload Image":"Upload Image","Upload up to 6 pictures":"Upload up to 6 pictures","uploading":"uploading","used":"used","user center":"user center","Upload Invoice":"Upload Invoice","valid now":"valid now","Validity period":"Validity period","View Cart & Checkout":"View Cart & Checkout","views":"views","Valid for":"Valid for","Welcome to the website":"Welcome to the website","Western Union":"Western Union","When your buyers received and confirmed orders, you can get commission right now!":"When your buyers received and confirmed orders, you can get commission right now!","Withdrawal":"Withdrawal","Withdrawal success":"Withdrawal success","Withdrawal Method":"Withdrawal Method","Write a Review":"Write a Review","Withdrawal Amount":"Withdrawal Amount","Yes":"Yes","Yesterday":"Yesterday","You are clicking too fast":"You are clicking too fast","You are got a coupon.":"You are got a coupon.","You can select a maximum of 90 days":"You can select a maximum of 90 days","You can withdraw the commission to your Paypal account.":"You can withdraw the commission to your Paypal account.","You haven’t chosen an address yet":"You haven't chosen an address yet","You haven’t selected a product yet":"You haven't selected a product yet","Your rating":"Your rating","Your review":"Your review","Your shipping address error":"Your shipping address error"}}