Canned Pump Protection (Electrical?)

[controlnovice]

We are specifying canned pumps for several services in the near future. We are discussing (read: arguing) about the various protection levels for the pumps.

Options:
1. Temperature switch in the bearings and/or windings. We will be using this as I believe this is a standard.

2. Level switch. This is new to me. It is said that the pumps need to verify that it is full before being started. Any comments?

3. Power Switch (low and high). I've installed these on Mag pumps, but not canned pumps. The mechanical engineer requested power switches on canned pumps now also, but I'm not sure I agree. Essentially these will be in the 10-20hp range.

Are there any standards out there to indicate what protection is needed on a canned pump?

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This is normally the space where people post something insightful.

 

[pennpoint]

controlnovice
#1 Good use them. Determine what temperature you want them to trip? How high/how low? Whats the $.

#2 Just how important is it to you that the pump is full at start-up, and so what if it takes more than a few seconds or a minute to fill. You need to determine if cooling is required at the outset or later on in the process. Whats the $.

#3 I cannot comment on "Power Switch", I need clarity.

#4 There may be standards out here but more than that there are requirements, and you need to state yours. You see standards do not cover everything.

Good Luck

Best regards
pennpoint

 

[rmw]

The question was well answered over in the motors forum. Canned motor pumps have no tolerance for running dry. Put the level switch, or prepare your piping so that they can be easily replaced.

rmw

 

[rmw]

Additonal comment; I did get a real chuckle out of some of my electrical peers first introduction to 'canned motor pumps' in the other forum.

rmw

 

[Artisi]

rmw (Mechanical) 22 Mar 06 22:37
Additonal comment; I did get a real chuckle out of some of my electrical peers first introduction to 'canned motor pumps' in the other forum.

rmw

Just hope they looked at the links for purely educational purposes.

Naresuan University
Phitsanulok
Thailand

 

[controlnovice]

Yes...sorry for posting this twice, but when the questions started coming, I thought I'd try here instead.

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This is normally the space where people post something insightful.

 

[Artisi]

For the motor size you are considering it should be sufficient to fit thermistors in the windings connected in series to a controlling relay in conjunction with over-current protection in the control panel.
Bear in mind, that every extra cable you run from the motor to the control panel becomes a potential problem for leakage of water into the motor unit.

Level control is necessary so that you have motor cooling.



Naresuan University
Phitsanulok
Thailand