what size generator do i need to power my kindlet 240 volts single phase

[mendiplogs]

We don't sell the Chinese stuff but you can pick them up on eBay for about £900 sometimes they last years if looked after often they last 15 minutes .

 

We sell a pramac p6000s last time I looked it was about £2500.00 +vat genuine yanmar engine and really quiet.

 

Hi Steve I'm told them P6000S are great thanks Jon

[cornish wood burner]

If it's 3 times current why only double?

 

As Farmer Tom said its a rule of thumb. Not strictly true as depending on motor design starting current can be 10 times running current. It's just a useful average. When a motor starts it has virtually a short circuit through the windings, as it runs up the back emf opposes the incoming current which quickly drops to normal. This is why you probably have b rated breakers in your house but a motor needs slower acting c or even d rated breakers. A breaker size of 2 or 3 times running current normally does the job but do not over size as its job is to protect the cable not the motor as many think.

Bigger gensets have more power, heavier windings, bigger breakers and more inertia to help cope with the high motor starting current.

[gensetsteve]

Hi Steve I'm told them P6000S are great thanks Jon

 

Probably the best on the market. Not perfect as it's still only a single cyl air cooled engine but as good as you will get unless you spend over 6 k. Incredibly quiet but make sure you get the p6000s and not the p6000. I think I have sold one this week but need to check how much I pay for them now.

[Richard 1234]

As Farmer Tom said its a rule of thumb. Not strictly true as depending on motor design starting current can be 10 times running current. It's just a useful average. When a motor starts it has virtually a short circuit through the windings, as it runs up the back emf opposes the incoming current which quickly drops to normal. This is why you probably have b rated breakers in your house but a motor needs slower acting c or even d rated breakers. A breaker size of 2 or 3 times running current normally does the job but do not over size as its job is to protect the cable not the motor as many think.

 

Bigger gensets have more power, heavier windings, bigger breakers and more inertia to help cope with the high motor starting current.

 

 

Thanks to both of you. It just sounded a bit odd:-)

[AardvarkTreeServices]

A breaker size of 2 or 3 times running current normally does the job but do not over size as its job is to protect the cable not the motor as many think.

.

 

Thats if you are using household MCBs and veiw your motor as consumable!! If you value your motor use a proper motor circuit breaker that will protect both the motor and cable with thermal and magnetic trips.

[gensetsteve]

Thats if you are using household MCBs and veiw your motor as consumable!! If you value your motor use a proper motor circuit breaker that will protect both the motor and cable with thermal and magnetic trips.

 

The domestic house hold breakers are often more accurate and kinder to the windings than the stuff fitted to small generators as standard. Unless you spend a lot of money it will be difficult to get a breaker to prevent a gradual overload. If the breaker cuts out at exactly 10 amps then it will pop every time you start a motor. The best thing to protect your generator windings is the operator.

 

Guess how many amps you can build up gradually on a 13 amp plug fuse before it blows.

[AardvarkTreeServices]

The domestic house hold breakers are often more accurate and kinder to the windings than the stuff fitted to small generators as standard. Unless you spend a lot of money it will be difficult to get a breaker to prevent a gradual overload. If the breaker cuts out at exactly 10 amps then it will pop every time you start a motor. The best thing to protect your generator windings is the operator.

 

Guess how many amps you can build up gradually on a 13 amp plug fuse before it blows.

Your probably right about the std motor protection, but a properly sized motor circuit breaker will fully protect the motor against short circuit/locked rotor AND gradual thermal overload. Quick search on fleabay and theyre about £25-30 which aint alot to save your motor and associated downtime.

[cornish wood burner]

Thats if you are using household MCBs and veiw your motor as consumable!! If you value your motor use a proper motor circuit breaker that will protect both the motor and cable with thermal and magnetic trips.

A household breaker trips in a quicker time than a motor rated breaker. The motor rated one is designed to trip slower to allow for the large starting current. Neither are designed to protect a motor. Both are thermally activated.

A motor should be protected by a motor overload which needs to be adjusted to maximum running current found on the motor plate. Again thermally activated.

 

For example a motor with a max running current of 5.9A could have a motor rated breaker C20 to protect the cable. C is trip time 20 is current carrying capacity. A heavily loaded motor with a heavy load such as a compressor might need a D rated trip to allow a longer start time drawing a high current.

The motor will be protected by a motor overload which on installation will be adjusted to 5.9A. This allows for the heavy start current but if the motor stalls the overload will trip to protect the motor.

Overloads are infinitely adjustable, breakers are available in set ratings.

[AardvarkTreeServices]

I think we're getting terminology mixed up. The motor circuit breaker I'm taliking about isnt a type D minature circuit breaker. Its a combined instantaneous and overload trip and is specifically intended to protect motors from short circuit and overload. Nothing like a household MCB as in minature circuit breaker. Typically a telemech GV2 or Siemens 3RV

[cornish wood burner]

I think we're getting terminology mixed up. The motor circuit breaker I'm taliking about isnt a type D minature circuit breaker. Its a combined instantaneous and overload trip and is specifically intended to protect motors from short circuit and overload. Nothing like a household MCB as in minature circuit breaker. Typically a telemech GV2 or Siemens 3RV

 

In my day job we normally call the distribution board or cabinet mcbs "breakers" and any motor protection devices such as you have named "overloads".

Sorry for the mixup but it's common terminology with the engineers and electricians I deal with.